I would get something like a HD 6850, HD 6870, GTX 560 or a GTX 560 Ti. If you can find a second hand HD 7850, that would be the best. Which games do you play?
I play a variety of games, like skyrim,crysis, battlefield, LoL, TF2,HL2. I'm really just looking for the most powerful card with the best bang for buck under 160$.