Good build, If it were me i'd personally pay up the extra bucks for the 2600k, but hey, gaming doesn't focus on the hardly at all. That graphics card should cut through skyrim, cod4, and gta 4 like butter.
2600K isn't needed for a gaming system. If you're running CS5 or 3-D rendering programs then it is.
That's an excellent build - I would have probably suggested the exact same system.