TL;DR: GTX 1070 is awesome, Corsair Air 240 looks great, i5-6500 is rock solid.
I mostly play RPGs like The Elder Scrolls or The Witcher. I currently have a 1080p monitor, so my next upgrade will be a 1440p monitor.
I'm coming off of a laptop with integrated graphics (obviously I did not play The Witcher on that), so the GTX 1070 blew me away with an average of ~130 FPS on Shadow of Mordor. I feel bad if I play Stardew Valley on this rig. It's like the computer scoffs at me.
Modding Skyrim has been fantastic. I can't believe how great everything looks.
I was able to save money by getting Windows 10 free through my University.
As for the title, I learned that PC building is way easier than one might think. Certain figures in the gaming industry should take note.
To Do List:
Add White Sleeved Cables with modular PSU
PWM fans and an aftermarket cooler. Fans that came with case are only 3-pin.