I always ran 2 x 8800 GTX's in SLI. They were the bomb.
However one died on me.
I recently bought one cheaper 9800 GTX and she handles pretty much every game I throw at her at max settings on her own.
Mass effect 2, Bioshock 2, Oblivion you name it, all look extremely good. (all in 1920 * 1200)
For just 135 bucks it's pretty cheap bang for the buck