Within your budget, where all your components fit and with focus on airflow (front mesh panel), take a look at those 4,
pcpp: https://uk.pcpartpicker.com/products/compare/jrVBD3,R6rcCJ,2pVBD3,ZHmxFT/
Specs;
Phanteks:
http://www.phanteks.com/Enthoo-Pro-M.html
Fractal Design:
https://www.fractal-design.com/home/product/cases/focus-series/focus-g
Silverstone:
https://silverstonetek.com/product.php?pid=659
Cougar: https://cougargaming.com/products/cases/mx310/
Since choosing a PC case is personal choice, go with the one that likes you most appearance wise. I, personally, would consider Phanteks (good build quality) or Fractal Design (miniature version of my Corsair 760T V2 case which i have for my Skylake build, full specs with pics in my sig).
E.g making the complete build look like so,
pcpp:
https://uk.pcpartpicker.com/list/GmTqw6
Made few changes as well:
* Removed MX4 thermal paste since NH-D15 already comes with thermal paste. Keep MX4 if you think it's better than the one offered by Noctua. (I too have MX4 thermal paste in use with my Skylake build.)
* Also, replaced low build quality EVGA 600W PSU with good build quality Seasonic Focus+ 650. (All my 3 PCs: Skylake, Haswell and AMD are also powered by Seasonic.) Since PSU is the most important component inside the PC, you do not want to use low quality PSU, if you care about your system.