Not much.
Graphics is what is most important for gaming.
Do not use sli unless you need to.
It is not needed unless you are using a 4k monitor or are using triple monitors.
With your budget for cpu/motherboard and graphics card, reverse your budget.
Spend $500-$700 on a GTX780 or gtx780ti and $230 or $340 on a i5-4690K or i7-4790K and a z97 motherboard.
Not so crazy about water cooling either.