cin19 :
Asus P8P67
Intel Core I5 2500K
Ram DDR3 KHC1600C9AD3K/4G 2X2GB
ATI XFX 6850 1GB (good for 1680X 1050)
http://www.tomshardware.com/reviews/radeon-hd-6870-radeon-hd-6850-barts,2776.html
While this would be the ideal setup out of the listed parts, I'm guessing it's out of budget. By like $100-200. Also, "good for 1680x1050"? Really? The 6850 is more than powerful enough to play the vast majority of games at 1920x1080 with high/max details.
For a gaming machine, the GPU is much more important than the CPU. While the i5-2500K is a great processor, it's also pricey. If affording it would require a huge sacrifice in terms of GPU power (dropping from the 6850 to 5670), then it's not a good idea. The 5670 would only be good for playing the most basic games, not the majority of games out there. The X4 955 (the cheaper, just as powerful brother to the 965) would be just fine.
I would also check out the ASRock 870 Extreme3 for the board. It's cheaper than most Asus boards, but it's high quaility, high performance and packed with features.