Wow... this is going to be the 2nd longest post in recorded history.

(I hope you won't mind if I cut some parts for readability)
Nope, I had lots of rambles and it was more than I even wanted to read.
Do not judge the new tag simply because the current implementation hits your CPU. That's not the tag's fault. And did you check the format of the video? Maybe it's in H.264 and you're not used to play that format (I don't know which format is used by Flash HD, or even if Flash HD is limited to a single CODEC).
My comp handles 1080p(H.264) QT trailers full screen on my 30' just fine. I do video work as one of my staples, so I'm familiar with it. =)
Flash HD uses H.264 with the latest player. YouTube is switching to it, which is good thing, because it requires Flash 9, which is considerably faster than Flash 7 and will use a system's GPU to render the video. On2VP6 could do 720p, but it was a CPU hog for videos of this size.
I guess those that aren't happy with Quicktime, WMV, FLVs, will support this format. But unless my clients ask for it and there's a good reason to use it, I won't be working with it, because it's toooo limiting right now when it comes to features and support.
I didn't really notice if it loaded/preloaded the video as my connection is too fast to see anything happening before it starts playing (5Mbps cable connection).
I'm cheap, so I only pay for the 6Mbit down via the EVIL that is Time Warnner, but that's more than fine for 720p HD QT clips and OK for 1080p clips. I tried it again just now and it was better, it loaded 3%, then 10%, then played. WHy does it even need a preloader? I'll excuse it though, since lots of Flash guys still unnecessarily preload videos.

I should try it on my PC to see what happens. I like the fact that they used QT as the wrapper for their example. =)
I'm glad to see a Flash coder who's worried about file size. As for streaming, well, to be honest since I didn't see any problem with the HTML5 video tag demo, I thought it was streaming. If it doesn't support streaming, then yes that's a huge roadblock right there. Also, someone mentionned DRM and file-grabbing. I didn't even think about that!
I started in the game industry back in the ninties, so we had to optimize all art down to the pixel. Before that, I was into pixlel painting, so I've always been weary about my overall size. I'm guilty of some bloated Flash in my early days, but even then, they were still smaller than other similar sites, but still they were way too bloated by what I deem expectable now days.
My point is that Flash, as a video/music player, could very well be replaced by Quicktime (it would still be a proprietary plug-in, but in reality it could also be replaced by VCL or something else or browsers could even start adding a built-in media player for a range of standard formats, just like there is GIF, PNG and JPEG for images).
As for this "HTML5 video" you seem to refer to, I think you might want to check the documentation again. We're talking about a simple HTML tag which references an external file. There's no magic involved here, no wrapper around the actual video file like FLV (FLV which won't play in Quicktime or iPods as an example).
I like the idea of this and QT is still my favorite video wrapper by far. But here are areas that concern me:
-If it's anything like SVG, I'll be limited to what features I can use, since most browsers will not be on the same page. Look at how IE has hindered PNG support an imagine that with this video support
-- I hate IE, but I still support IE 6 on all of my sites.
-With Flash, I can put my file online, or in a Projector that works on any Mac or PC, even if they don't have Flash Player installed. With this, the user would be reliant on their browser, which leads back to my first point.
I can export FLVs from QT. =) Adobe could offer a desktop plug-in for FLV playback through QT. It would be just like Flip4Mac for WMV playback. I know what you're getting to, but only QT plays on an iPod. ^.^
In that particular case, I'd rather see Flash everywhere (especially given that it now supports H.264).
Always a good thing. Thankfully WMV 9 didn't become the standard.
I actually had to search to see what SEO meant (search engine optimization - it's bad practice to mention an acronym without a reference to what it means the first time you use it)
Sorry.

I get lots of requests for it -- especially with concerns about how to handle it with Flash, so I was in a set mode.
I was talking about the majority of websites in general yes, but mostly about commercial websites. And I really don't encounter Flash that often (or if I do, I don't see it and it's not required, as I browse with plug-ins disabled).
But how will you view Shockwave content. ¬¬ My friend does the same, well sorta, he moves the Flash plug-in out of its folder, but I think he does so just to annoy me.
Indeed. It doesn't matter if annoying banners are made with Flash, in video or simply animated GIFs. If it's annoying, it's annoying.
And if you want REALLY annoying, click on this
*WARNING* link. *WARNING* keep your fingers on command-w. =)
I agree that for such demos, HTML would be poor (even with Ajax) and that videos are just too "static" (i.e. no interaction).
Comment about Flash in PDFs: aaaaaaaargh.
I keep seeing those kinds of problems, so it's not "10 years ago" as you say. Unless of course the websites are 10 years old.
And you probably thought PDFs couldn't get worst.
I only goto Macrumors and a few other sites on a regular basis, so this is probably why I'm not bothered by the EVIL that still exists. =o
But that's my point: Flash has access but the programmer has to access those features, they're not active by default. When I code a website I don't have to code scrollbars so that they work with the mouse scrollwheel, for example.
Everything you say after that validates my point: you need to USE the features, Flash doesn't do it for you. And that part about requiring a special "macscrollwheel"? Come on. With HTML, the scrollbars just work.
As for the printing, well-done CSS websites don't have a "print button". We do need to make a special printing version (as in Flash), however it's all automatic.
Flash is definitely not a good solution for most and most don't need what it can offer, but like I said it's a trade off. If you need/want something 'way' beyond what HTHL can offer, something that can live on a desktop, can guarantee consistency across the board, than Flash is one of the best options available right now. It's an extremely powerful and wonderful tool, that happens to know how to speak web. Like anything that's this complex, it has a steep learning curve; It's not for the meek.
I prefer the simplest approach, but I can't build a tile-engine (2d Game engine. Tis my hobby.) in HTML.
I can make it so that the bars just work, but it requires JS to resize the div-cell Flash lives in. *OK, that doesn't just work..* =O This is how I normally handle it and until recently, wouldn't have considered any other option for Flash. But... because of a NASTY bug in IE, I had no other choice but to do something quite EVIL with my new site, and that was to create replacement scroll-bars from scratch. If not for IE's popularity, I would have never done this,. It was either make a huge compromise on the design, or go forward with it. Anyways, they work quite well, so I don't feel to bad about doing this unthinkable act.
With HTML you print everything on the screen.

If that's fine for your need and your clients/visitors, than cool. If you ever need more control, well... Custom fonts galore on any browser, not just Safari and no print-friendly screen required. =)
That's my point: it's not an option, it just works by default. Ever heard of screen-readers? I'm guess you don't.
I'm not talking about font control or zooming abilities. I'm talking about a special browser which reads the content and speaks it out. You're SOL if you're blind and encounter a Flash site (even if only the navigation is done in Flash).
And BTW there's nothing to code for keyboard navigation in HTML either. It's all there by default.
I wasn't thinking of blind people.

*hides*
I see what you're saying. I do put all my copy and links into actual HTML pages, but a user with Flash enabled would not see them, since it parses this info into Flash and formats it accordingly, so they're always on the index page. But do you think a blind person would have Flash installed? If not, then my newer sites would be accessible. I build everything in XHTML and because Flash does all of the heavy formating programmatically, the pages are quite simple, really basic templates -- similar to an XML web page.
I'm browsing with Safari 3.1 right here and I don't have Flash. It's disabled. Don't think that because it's there, people want to use it. If I could disabled animated GIFs in Safari, I would do that too.
And before you laugh, understand that a lot of people, like me, disable plug-ins because of the Flash banners (I even disabled Java). If there is stuff moving on a page I'm trying to read, well, I just can't read anything. Surely you must have seen some annoying animated banners (Flash or not), so I hope you understand.
Also, browsing with plug-ins isn't that far-fetched, there is even people browsing with javascript disabled.
And if I'm seeing the website anyway, and you take time to code it correctly (in (X)HTML/CSS) then it means you're coding the website twice, which costs twice as much for clients... :?
FYI, Flash works great in 3.1 BTW.
I understand, It's your choice.

But just know that someday you'll be in a trade show and bam, you'll see Flash again. And think about all of the lovely training demos you're missing out on. =)
I'm the same about something distracting me while reading. I generally scroll my page to hide it -- if possible, or resize my browser window when this happens. All banners should only play once and require a click. Does disabling Java get rid of the EVIL sliding DHTML banners.
You may be able to do lean Flash stuff, but as you say, most Flash coders don't see to be able to do that. I remember that my Mac mini G4 was brought down to a crawl by full-page Flash, having to wait 15 seconds at about 3 frames per second for a page-changing animation before I could access the content of the next page.
As for Flash beating HTML/CSS, I'm guessing you have never seen a really well-done HTML/CSS (just like I have never seen a well-done Flash).
That site SUCKED, why did you visit it.. =D I'm OK with initial CPU hits, because all sites weather it's HTML or not will do this, but anything that does not idle down quickly, or idle low in the background, really bugs me.
Kind of related, but not... My friend tried to tell me that it takes 10 seconds to load the Yahoo page on his MacBookPro, and he blamed it on Flash. I just sent him a video of my old DP 1.2Ghz G4 loading Yahoo's page in only 2 seconds with Flash on. Is this an Intel issue?
And if my last 1Ghz PB hadn't died last month, I would still be optimizing/testing my work for it.
Given a designer has the knowledge and directions, Flash can DESTROY

any HTML/CSS site a new one and I mean that quite literally.

Think of it this way, if you could take your art directly from Photoshop -- assuming you work as an artist

-- onto a web page, without needing to flatten and slice the art, then format it using HTML, so bring over all of your layer-effects, drop-shadows, glows, alphas, etc, and place them exactly where you want, this is Flash. It's more like AfterEffects though, since it can also do that animation stuff and handle video.
Now this is where Flash is way better than any other web-tech, its Bitmap API allows it to draw really complex elements at runtime. This allows it to be completely dynamic. I'm not exaggeration when I say that one could draw Safari's appearance, so it's brushed aluminum look along with all of its buttons, bars, etc., all with just code. So absolutely no imported art.
For my sites, I draw some elements -- generally all of the button -- with the Bitmap API, other parts I import as optimized art, which I will composite with other elements to recreate the look I had designed in PS. This keeps the files size way down and doesn't hit the CPU any more than any other site on its initial load. I will provide examples if you'd like?
You're validating my earlier points again. Flash programmers need to code things that simply work by default in plain HTML websites (scrollbars + mouse scrollwheel as an example again).
I don't argue that Flash is powerful and flexible. I don't quite get your "can be shared" comment... Text can be selectable but has to be added in your code, something which, again, "just works" in HTML.
Yes, but you're SOL when a new platform comes out which doesn't support Flash (and being a proprietary format, there's nothing you can do about it). And Java has come a long way too, just like Flash.
All languages/platforms have developer communities, and they all have their share of crap. It's just that with Flash, you also have the requirement of a proprietary plug-in which requires both Adobe and your platform to support it. For browsers, you have a choice between IE, Firefox, Opera, Safari, to only mention those.
I'm quite sure that the video part of Flash would be the easiest to implement. All those scripting and vectors parts are no doubt the hardest.
Same here.
It just works, because that's all it's needed for. Hyper Text Markup language. =)
If you need Flash, or something similar, having to define a text-block as selectable or not, is a good thing. You wouldn't want someone selecting text from a drop down menu as an example. It's a programming environment, it's for building applications, it has to have this flexibility. If you're just building a blog as an exapmle, than Flash would be an overkill,
but I would still do it... =O But if you need something more than just a HTML/CSS page, than you'll have to move to a development environment like Flash, or Java.
It's proprietary, but it's widespread and I know that 99.9% of all of its features work every where the 'target' player is installed. It has the backing of Adobe, which has made it better and this is absolutely needed. As long as Adobe continues to back it and my client's ask for it, I'll stick with it. If a day comes and I'm required to move to a new tech, I'll do so. I moved from Director to Flash. At first it sucked, but now I won't go back go back.
You can always tween in Flash. =) Animating in Flash is actually quite easy, but if you need it to be dynamic, then you'll have to hit the code. But in order to get to the goodies, beyond components(standard video), you'll need to know how to program. When I started with Flash, I was always on he timeline and stage, now I'm always in a window with lots of color coded text.
*I ran out of allowed happies!*
<]=)