Gtx 460 768mb or 5770?

My wife is letting me have a budget of 170 and i want to get a good grahpics card intill the 6000 series comes out i wont crossfire intill the 6000 series comes out i would like to get a card now. The Resolution i game at is 1600*1200 i have a gigabyte 890fx Amd phenom ii x4 955 @ 3.6ghz the only games i want to play are Battlefield bad company 2 and Medal of Honor 2010 with no AA or AF would one of these cards max out these games? Which will give me best bang for buck? Thanks