A 320MB 8800 GTS is just as powerful (more powerful, if overclocked!) than the 640MB. Unless you're running 2048x1536 in Ghost Recon or something, you'd be happier with the 320MB, and it's cheaper.
Its the same base card but please lets not get ahead of ourselves show me where the 320mb version is more powerful?
I think the 320mb version will be a fantastic buy , great for people who dont have the means to get the real 8800GTS
The key words are "if overclocked" You're absolutely right, though--same base in 320 and 640 MB versions. HUGE performance-per-money ratio on that 8800GTS 320! It will, however, fall behind the 640 at crazy high resolutions, but I recommend it 150%. I just put one in my sister-in-law's new computer and it's a screamer.
500W should be OK, but if you can shoot for 550-650 it would be better. Make sure it has at least one PCI-E connection (6-pin).
mmm, i use the 7600gt for all my clients in the base modelsIf it is any indication, I have a 7600GT and I run Counterstrike at my Max Resolution 1920x1200 and do not get a hic up.