So hey PCPartpicker community, I did this build back in 2016 for 3D modeling, Vegas rendering, and gaming. It has served me pretty well but I do have a few regrets.
First of all, the rear cable management space in the Define Nano S is horrendous, and there is no way that back panel is going on. I also had a few hiccups during installation. The I/O cover that came with the mobo did not fit in the case, and there was a chip on the rear of the Z170 Stinger preventing one corner of the C7's bracket from going in. Also, I shouldn't have let my sister step on my plexiglass side panel. (oh well)
K65 RGB is great, I do have a few dead pixels on it though and it is a pain to clean. MX Master is the best mouse I have ever used, and feels like heaven compared to a portable mini mouse I used to use on my iMac. (I hate Apple now lol) The two 23 inch Dells were a steal for $100 a piece, and I have had no issues on any Dell monitor I have used. ADATA SSD is fine, although it and the Barracuda filled up very quickly. XFX PSU is very reliable and works great. As for the GPU, R9 390 was the way to go compared to a GTX 970 because of the 8GB of VRAM which is great for my use scenario. Cable extensions work fine and also look great. Overall I was and still am pretty satisfied with this build, but the time to have a second PC is coming I think.
K65 RGB is great, I do have a few dead pixels on it though and it is a pain to clean.
MX Master is the best mouse I have ever used, and feels like heaven compared to a portable mini mouse I used to use. Highly recommended for 3D modeling, editing, and even gaming.