I should add that Intel has a new CPU, code-named "HASWELL" (probably an i5 and i7 4000 series) which is coming around JUNE or so.
If you can wait to build your computer, I strongly suggest you do so. If naming conventions continue, the following MIGHT be the next recommended gaming CPU at about $240:
The reason I recommend waiting is that Haswell can massively reduce power consumption (mostly in idle). It's not just a 10% improvement, apparently it's supposed to be a huge difference because the CPU can rapidly turn off and on constantly thus managing OFF states while the computer is "running".