If budget is not an issue, the GTX980 is the best.
Otherwise, a GTX970 will be almost as good.
For either, I would pick a version with a stock blower cooler that efficiently gets heat out of your case. EVGA makes them.
On the rest of your build, here are my thoughts:
1. 4690K is as good as it gets for gaming.
2. Dump the liquid cooler.
I have become a bit jaded on the subject of haswell cooling for overclocking.
How high you can OC is firstly determined by your luck in the bin lottery.
I had high expectations from the Devil's canyon parts and their better thermals.
I found out that the thermals really do not matter unless, perhaps, you are a competitive overclocker.
Haswell runs quite cool, that is, until you raise the voltage past 1.25v or so.
Once you go past 1.3v, then you really do need very good cooling to keep stress loads under say 85c.
But, voltages higher than 1.30 are not a good thing for 24/7 usage.
Even if you can handle the heat, how much do you really need that extra multiplier from say 4.4 to 4.6?
My thought is that it is better to use the exotic cooling funds for a quieter and less expensive air cooler.
Anything extra can go to a stronger graphics card for the gamer or a SSD.
3. Are you a fan of fans??
Start with the supplied case fans.
You will have adequate airflow for your parts.
Fans do not cool, your parts do not sweat. The purpose of fans is to get hot air out of your case.
More or stronger fans will add noise and expense to your build.
Wait and see if you really need more.