Please critique this custom build

Here is the link to the online custom build:  http://www.cyberpowerpc.com/saved/1JKQLA

Based on my research and budget, I feel these three components are a must (but I am open):

1.  i7 6900k

2.  GTX 1080

3.  64GB RAM (quad channel, 2600 or higher speed)

Obviously those three dictate all the rest and the rest is what I am most unsure of.  Well, I do like the idea of having an M.2 SSD, youll see that selected in the build.  I just want to be sure the mobo and the rest will allow this M.2 drive to actually reach those crazy (well over normal SSD) speeds.

I truly appreciate any help you all can throw my way.  Thank you.