Most bang for the buck?, Hmm, wanna say ram, but, vid card. Yeah, that's it. a vid card with ram. It lets the proccesser do its thing, while it does it's thing.
The_Dude, I hate to appear snooty, but, unless you are playing pong in 3d, 500.00 is not a gaming machine.
Or, you have some juice with the manufacturers.