How does this build sound?

Solution
It looks good, except you don't want to buy 2 separate kits of 16GB (2x8) RAM. RAM is sold in kits for a reason. RAM from the same vendor and part number can be made up of differing manufacturing components which can cause potential RAM errors and issues. My advice is to buy a single kit of 2 x 16gb ram (32Gb). It's just a little safer this way, so you're guaranteed not to have RAM issues from two separate kits.
 
1). Personally I'd recommend a GTX 1070 or 1080 if you're going to be spending a lot of time in 4k, especially double 4k monitors.

The GTX 1060 only has 6gb of VRAM, and no SLI support (technically). It's generally regarded as a top-of-the-line 1080p card, but a stretch for 1440p, and a real stretch for 4k.

2). The two network cards are usually not necessary, but you might be running some stuff we're not familiar with so props if you are.

3). This PSU isn't that bad in my opinion, but it's sort of low on the "PSU reliability hierarchy".

Good luck man, you have a good build. Make sure that once you get your graphics card to verify which monitors will be running displayport and which will run HDMI.