Originally Posted by
mattyp
What is your budget? Intel is better but also more expensive, if you are in the sub $750 range than I would suggest AMD Phenom II CPUs, in the sub $500 range than the AMD A series APUs because at that point you can't afford a GPU.
Anything higher than that I would suggest either a Intel i5 2500K or i5 3570K. The 3570K is more expensive but also a lot better. I would not suggest an i7 because the only advantage of an i7 is hyper threading and games don't support that anyway. The 2500K would be plenty for gaming but if you have enough room in your budget for a high end GPU and still have money left over, definitely get the 3570K in order to give you some longevity.
If you give me a budget I can pick out a parts list for you and if you live in the US I will even assemble and ship out the computer to you for a very small fee if you can't build the computer yourself. The advice and parts list is free, the building is not.