thought I'd put up my experience if it helps, since it is pretty similar to a few users who posted here in this really fascinating thread lol.
I bought a 1950proagp 2 days ago at the same time as a new 22" LCD monitor at 1600x1050? or whatever the native is...
I have a socket 939 athlon64 3200, 1gb DDR1 non dual channel RAM, 450W PSU (working for now, whew!), 3 HDDs and an Antec 900 case.
my previous card was an x800gto with zalman cooler overclocked around 15% with atitool, with a 17" crt running 1280x1024 desktop and 1024x768 games. boy was I spoiled with 30-32 degree (celsius) gpu temps. now I am seeing around 50 degrees idle (with very good airflow) and it sure makes me anxious!
One thing to consider here, is resolution. I am a bit afraid that future titles could be hard on my system sooner rather than later, but I really needed a better card to support such a high res monitor anyways. I found that BF2 on all high settings and forced to 1600x1050 res runs well, but I confess it does drop some frames noticeably in a multiplayer server during action. I don't know the FPS because I could'nt remember the command when testing last night.
WoW with all maxed settings is a real treat in colour display on my new monitor. However, Just running around the world in general is netting me 30-40fps, and I feel WoW is a pretty low demand game. I imagine I will have to reduce a few settings a little to run instances well, but overall I am generally satisfied. I'm a little disappointed that I don't have 80+fps with my new vid card, but with such high res I'd be dreaming for that lol.
what it boils down to: playing games at high res is really nice, and many monitors at these resolutions are very affordable now. Even for us lowbie AGP users, these kinds of cards are still useful for having a nice high-res screen for quality movie watching, picture editing, etc without having to shell out for a new mobo, processor, ram etc to go PCIE. Maybe I'm a niche market with a nice monitor and a (relatively) low end enthusiast pc, but this card treats me well at least.