Usually a gaming computer is going to run an i5 processor as it is all that is needed, so depending on the model you want to go for , Ivy Bridge or Haswell you would be looking at an i5-3570k or a 4670k.
If your going to be doing any video rendering or photo editing then you would jump to an i7, either i7-3770k or i7-4770k.
If you just plain want to use an i7 because you want to then I would go with the i7-3930k because the X-79 chipset and LGA 2011 socket processor will give you 40 lanes of Pci-e bandwidth to run your video cards at the full x16 bandwidth even if your running two cards..