[Build Help] What is the most logical cpu choice for my XFX HD5670?

So I have this HD5670 laying around and I want to buy a pc for it.

I also have a 1tb WD green caviar.

Basically a CPU recomendation (what is the cpu that pairs nicelly with it for gaming)

Aiming to play Heroes of Newerth

Bad company 2 (hopefully BF3 too)

Diablo III

Magicka and Skyrim.

I was thinking to get an i3 2120 but im looking for sugestions.

Thanks in advance.