The i7 2600k is over kill for gaming. You would use only abut 40% of tha CPU. Some of the gamers use the i5 2500k because it is in line to run with most all the GPU's. As long as you have the right PSU.
The GTX 570 or the GTX 560 Ti would both work good with the i5. There would not be any chances of the CPU keeping up with the GPU. We should be seeing the new Nvidia Kepler out next month.
So if you wanted to wait you could do that as well. The i5 is a lot cheaper than the i7, so you could put the difference on a second card and go SLI or put the money towards the new Kepler. Just food for thought and good luck to you.