These are the best-buy processor right now, from cheaper to more expensive:
Intel i5 4570
Intel i5 4670k or Xeon E3-1230V3 (this two have about the same price)
Intel i7 4770k
i5 4570 is for you if you have somehow tight budget but still plan to have a decent rig but no OC
i5 4670k is for you if you have better budget and plan to OC
E3-1230V3 is for you with better budget, want to have i7 4770 performance, do not plan to OC and do not need the iGPU.
i7 4770k is for you with premium price willingness, want to have super performance, and plan to OC.
Note:
i7 4770k or Xeon E3-1230V3 is not needed for gaming today, future of gaming with 8 cores/HT is still uncertain.
My favorites are i5 4670k and E3-1230V3.