Honestly ur better off getting the parts of the first build, buying them separately. and instead of getting the 2600k get the 2500k or 2500 if ur running at stock. and spend the rest on a Gpu like a 6870,6850, GTX 550Ti,460 or 560.
That is a subjective statement...it really depends on the game manu 11.
Last I read most games do not benefit from multi-core cpus, but that is changing. Games do get an indirect performance boost as other processes can run on cores not being used by your game.
But for the price posted and for the components you get, that system should do nicely on most games with moderate to high settings and a good resolution. I feel is a better buy than what the author listed, but hey the main thing is to look around you can find good deals, IMHO.