I am building a mostly new System mostly for gaming. I have set a price cap of about a grand.
I have priced out 2 systems. One system with an 15-2500k and a Nvidia 470. The Second is an 17-2600k with Nvidia 460. Where is my money best spent with the lower in graphics card or the lower end processor?
The 2500K is all you need for gaming. It will OC just as high as the 2600K, and few games use more than two cores, certainly not more than 4.
Spend the $100 difference on a better graphics card, and you will be happier.
Gaming won't make use of the extra threads provided by the Hyper-Threading Technology in the i7-2600K. It usually doesn't even make use of any more than 3 cores.
The best price/performance configuration for gaming is with the i5-2500K and the higher performance and bandwidth graphics card and an Intel P67 Express chipset motherboard so that you can overclock using the unlocked multipliers.