Hawkshot :
Unless you are looking at streamlining while gaming or doing a lot of rendering the I5-6600k will be the best choice for a cpu, give it a nice CPU cooler and overclock it a bit and you're laughing, I haven't found a game yet I cant play on ultra at 1080p with my i5-6600k and R9 290x.
Any i5 will start "bottlenecking" cards like GTX 980 and better.
Examples: DOOM, Crysis 3.
R9 290X is not there. GTX 970 is also willbe fine with i5. But newer/better card will not.
OP should not buy CPU to match his current GPU, but have some headroom for GPU upgrade.
for example, ~40% of GTX 1070 will be wasted with i5 in games mentioned above. The list is much longer, those i play personally.