btw i wont be playing just bf3, maybe some diablo 3, arma2 dayZ, and alot of games....
bf3 is one of the most demanding games out on the market atm. the other games you mention are all FAR less demanding than bf3. long story short, if a card plays bf3 well, chances are it can handle anything else you throw at it (at least in the current market).
anyway, the 480 typically gets my recommendation, the 7850's your safe and conservative choice (due to the 480's power draw and heat issues with insufficient cooling)