New
#11
You don't say what resolution you will be using... if it's something fairly low like me (1280x1024) you could probably get by with a card like the Nvidia-based GTS 250, or the ATI 4850. You should be able to find those cards for about $120 online for the 1 GB version.
But if it's a higher resolution like 1600+ then as others already suggested you'll need something like a Nvidia 260 GTX or ATI 5770, which I think tend to be in the $180-200 range.