Websites giving you problems
Hi there!
I have the same Hi-Res PowerBook G4 as you do and for the most part flash doesn't really bother me as much.. Please send me an example of what websites you are using and I can see for myself if I have the same problems.
I do wish you luck since your machine won't handle those sites, or that it does just that the PowerPC isn't cutting it for you. What is really interesting is why the G5 Dual core and Quad machines can zip through flash with almost no problems or slow downs? I watch mostly youtube and videos using Quicktime, but flash isn't that terribly slow on my machine.
Again, I am sorry to see you give up on the 1.67 PowerBook G4. Its still a nice laptop for what it can do. Have you tried lighter web browsers such as Webkit, AuroraFox and or SeaMonkey? Those might help in the interim.
I pretty much use my PowerBook G4 1.67 for not only basics, but for small computational stuff and blogging + facebook. Then again I have an SSD drive in my PowerBook, so things load up quicker, compared to a mechanical drive.
Again, send me some links to some of the websites giving you problems and I can try to see if I can zip through them without any problems. I modded my PowerBook G4 1.67 to tackle flash and complex flash sites.
Best of luck to you, and keep the PowerPC ALIVE!
PPCMM
I'm as big of a PPC fan as anyone, but my PowerBook 1.67 needed to be superseded by a MacBook yesterday. What surprised me was that it didn't involve CPU intensive programs, just little bugs and general slow-ness that made me switch up.
I'm a marketing intern doing SEO, blogging, and a lot of social media riffraff. Unfortunately, the websites I need to do this are either flash based, or hit me with an "Unresponsive Script" error when I try to use them. (Google AdWords) With Excel and Word open, and 5-6 tabs in TenFourFox, the computer had no problem "Beach-Balling" me numerous times, and I had to Force Quit a lot of things.
I was really hoping this computer would get me through my internship, but it looks like what is commonplace in the 2013 World Wide Web has finally killed it for me.

If it weren't for the poor internet performance (due to the graphic/animated nature of most websites today) I feel as if this computer would be very viable for what I do, which isn't that intensive of work.
Computer Specs: 15" 1.67 Hi-Res PBG4, 2GB Ram, 250GB 5400rpm WD Blue (Fastest possible PATA HDD, right under the 320GB version), Leopard 10.5
For now, it's back to borrowing my girlfriend's old 2.4 C2D 15" MBP. It works great, but as many of us know, just doesn't have that PPC "feel" to it.
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What do you use your PowerBook G4 for? What daily use do you mean. If you mean youtube, mactubes etc.. running videos and movies in Quicktime rather than flash is a nice solution. Office 2004/2008 is quite speedy on this PowerBook, except for maybe 2008 which takes a little longer, but I use Office 2004 and it hasn't given me any problems.
Blogging, Facebook, twitter, etc.. I do this on a constant basis.. Where the PowerBook G4 fails in most aspects is video rendering of course and encoding.. But I have my G5 for that and or 6-core Mac Pro.
Daily use for me means: Checking, reading, sending email, blogging, twitter, Facebook, video chatting, Youtube, videos, and word processing - ALL of which I have zero problems with on this machine. Its my daily everyday, work machine and is a pleasure to use. I AM not knocking Intel at all.. just that like you I too love PowerPC. I started my life with Macintosh on a PowerPC back in 1999. I have A+ certification with PC hardware and software, but none with Mac.. I gave all that up for Mac as I enjoy using PowerPC.
I have a G5 Quad which I use as my everyday home machine alongside my Intel Mac Pro for heavy duty stuff.. My Gateway P-7805u FX is a nice Snow Leopard, Lion, Mountain Lion experimental laptop which so far things run nicely on it. My G4 Pismo 550 I use for OS 9 based work.
I run Virtual PC 7.0.3 with virtual machines in BeOS, Linux, BSD Unix(FreeBSD).. I am well aware Windows runs slow. I don't use Windows on my PowerBook G4, though windows xp is still usable on this machine, though I have to turn off all eye-candy.
There is still plenty of life left in a 1.67 ghz laptop, in my opinion. But for daily use with standard applications I find it quite usable.
It is a good feeling! Still my favorite laptop in the house, just wish I could use it on a daily basis.