I suggest saving about $58 over the E8400 and get an E7200. The E7200 I think is the best bang for the buck as it can easily top 3.5GHz on air. http://www.legitreviews.com/article/690/12/
By OCing this CPU and putting the extra $58 on the GPU you will have a better gaming system.
Xbit even hit 4GHz on air but showed no OC'ed benchmarks.
Clock for clock and the same GPU the E8400 would win but spending the extra $58 on a GPU would make a huge gain in FPS. $58 will make the differance in you getting an 8800GT or an 8800GTS and anyone can tell you the 8800GTS is well worth the extra cost.