even with the 8800gts640mb, there are games that you cant play with everything on "high". my points is wait for next gen cards. games like rainbow six vegas is already killing the 8800gts640mb. so the 8800320mb is the way to go for now, dont let few games holding you back, its not worth it.
My PC plays Vegas with everything on high, 4xaa and 8xaf, same with all games I'm currently playing, GRAW2 is out in the next couple of weeks and people are saying it needs more than 320mb for high textures. Texture quality makes a huge difference to visual quality, I'd much rather have High res textures with low or no AA than medium textures with higher AA.
for the sake of $60 it's a false economy to skimp and waiting is silly, you may as well buy the best card you can afford now and enjoy it
remember how everyone said "wait 2 months for ATI 2900", which turned out to be 8 months of waiting for a products that's marginally better than a GTS
why pay extras $60 on just few games~~ and he doesnt even game @ 1680x1050 above. there are many good games out there and can be playable with 8800gts320. as for next gen cards that is the big deal since games like crysis or ut4 are not out yet, i mean i m happy with my 8800gts640 since that came with my build, but if i have some like x1950xt i will not even thinking about getting 8800640mb. not to let everyone down,but imo the 1st gen dx10 cards are a jokes, i dont think it can handles any dx10 games with good settings