I built this computer as an upgrade to my gaming laptop (Lenovo Y510p). It's a good laptop, and I plan to keep using it, but I wanted to have a computer that I could max graphics settings with. I also wanted the ability to expand into VR sometime next year once the systems become more refined and more games become available.
After much forum surfing, I decided on the i5 6600k for it's overclocking ability (also because I have no need for an i7). Initially I wanted to go with a GTX 1060, but I decided that the extra cost of the 1070 would be worth the ability to keep the same card for 2-3 years, hopefully.
As far as cooling the i5, at first I went with a Corsair h100i GTX because Newegg had it for $79.99 after rebate. After it was in my 70% complete machine, I noticed that one of the tubes was starting to come loose from the radiator. After removing the system, and wiggling around the tube to see how loose it was, it came free of the radiator and started leaking. Needless to say, I dodged a major bullet. After getting a refund for the Corsair unit, I went and purchased the Thermaltake Water 3.0 Extreme. Since installation, it has been working like a dream (and no leaking!).
Please leave constructive criticism in the comments if you see anything that could be done better, thanks!