They're all going to perform about the same, absent one's with factory overclocks, so don't get too hung up. EDIT- Forgot to say you should consider getting an r9 290 in non reference design.
As for the cpu, in a general sense a 4670k. Then again, AMD does have mantle and 8 core cpu's may be more viable for future gaming. Honestly, you can't go wrong either way.