Sure...99% of what you said is web-based...and web-based "computing" has been huge for about 10 years now...and will continue.
I agree with you and others that state many computing tasks have transitioned from thick client to web-based...as well as new web-based tasks being born (online banking, online shopping). However, there are still loads of thick client apps that simply don't port well to a tablet-based computer or web based system. Examples: MS Office (where you actually sit and type for hours), Audio editing, Video editing, Photoshop or other photograph editing, Winzip/Winrar to compress files, FTP access, chat software, backup/restore software, and of course the numerous web-based applications that either require Flash or require a browser that is better/more powerful than Safari. Those are a few examples.
As an owner of an iPhone 3GS, the iPad is just an oversized iPhone while removing features (phone, camera, GPS, poorer display than 4G) and adding features like larger display. At the end of the day, my personal computing tasks still require me to do things that an iPad simply cannot do: share files via industry-standard devices/ports (no USB on iPad), print (coming sometime in 2011 I think), use a true keyboard rather than a virtual one (I like the iPad and iPhone virtual keyboard but my typing is about 1/2 what I can do on a normal keyboard), use a mouse that has far more accuracy than a touchscreen (touch is nice, but sometimes it is a real pain such as clicking on the wrong link) and most importantly, is free from an Apple-monopoly-approval-system world of applications. Again, these are SOME examples of what I use my personal computer for yet the iPad cannot perform.
And contrary to your belief, I have used an iPad...for about 45 minutes (as I already used to the iPhone) and it just isn't "magical" to me nor is it anything near what I would....let alone worth dropping $500 for the basic barebones model that can hold about 2 movies and 400 songs at once. You? Sure...maybe it fits your bill just fine. Me? I'll wait for much future versions when it truly may replace my desktop/laptop.
-Eric