Some thoughts:
1. For midrange gaming, individual core speed matters. For that, look at a cheaper i3-6100,6300, or 6320.
Here is a review, Note that the i3-6100 generally beats the i5-6600.
http://www.anandtech.com/show/10543/the-skylake-core-i3-51w-cpu-review-i3-6320-6300-6100-tested
2. Non K skylake processors come with a stock cooler that does the job. It is about as good as the TX3.
3. Always buy a 2 stick kit of ram so you can operate in faster dual channel mode. 2133 speed is fine.
4. I would buy a better quality and slightly stronger psu. Seasonic is always good.
Pick a tier 2 unit from a list like this.
http://www.tomshardware.com/forum/id-2547993/psu-tier-list.html
5. FWIW.
I will never again build without a ssd for the "C" drive. It makes everything you do much quicker.
120gb is minimum, it will hold the os and a handful of games. If you can go 240gb, better.
Samsung EVO is a good choice.