Best CPU for ONLY Gaming?

Sup guys, making this new PC and im not sure what CPU to buy, im stuck with the i5 2500k, fx 6300, I really got no idea what cpu, was wondering if anyone could help me out, thanks for reading

EDIT, Im on a limited budget btw, so no $1000 cpu's or shit like that, =)

The i5 2500k/3570k are the best gaming CPUs without severely dimishing returns. You could get an i7 3770k but you won't see much of a boost if any, depending on your graphics card. The FX 6300 is great for computers on a bit tighter system budget ($650-$900), but the i5 will outclass it in almost every regard, theres a reason its nearly $100 more.