Quad Core vs Dual Core

[Soleron]

You might as well get a quad, they are very cheap now. If you want to compromise, you can get a tri-core too. I would say about half of newer games benefit from 3 threads and a little less from 4.

But if you have any money in the budget you should preferentially spend it on the GPU; framerates will benefit more.

In terms of CPUs, the best value from low to high are (in my opinion) the Athlon II X2 250, Athlon II X3 435, Athlon II X4 620, Phenom II X4 925, Phenom II X4 955, Core i5 750, Core i7 860. Anything beyond that isn't good value. At sub-$200 you can see AMD is better value, there are Intel options but they are overpriced; at $200 and over there are only Intel options.

I would wait until January 7 when Intel's Clarkdale comes out; I don't expect it to change the market much because it's priced high (3.2GHz dual for the same price as AMD has a 3.2GHz quad for a lower price), but you can look at reviews (I recommend techreport.com and anandtech.com ) to see which CPUs perform well in the games you want.