Multi-Purpose mini-ITX build

Couple of thoughts -

I'm not sure why anyone would buy a Xigmatek Aquila for an ITX build. It's fairly expensive relative to the competition, and doesn't really have a huge amount going for it when you consider the various alternative offerings from the likes of Bitfenix, Fractal Design, Corsair and Silverstone. Personally, I'd use this to cut the budget down a little.

If you do want to stick with the Xigmatek, I'd suggest considering stepping up to mATX. You'll arguably get more for your money, as well as more expansion slots, and less issues with fitting a suitable CPU cooler.

Speaking of which, I'd be fairly sceptical about fitting a cooler like that on this motherboard. It's really hard to get conclusive data on this, coolers can vary a little (even from the manufacturers specs as they measure things in slightly different ways) and things like graphics card backplates/rear components can interfere too. What I do know is that a Hyper 212 (similar cooler width) can have issues with Gigabyte and MSI boards, which have generally used a similar CPU socket location. Noctua, who provide excellent compatibility lists, state that their own 120mm fan-based tower cooler is not compatible for the same reason - clipping the PCIe socket, though theirs is a bit wider.
The ASRock and Asus models do not have this issue, though the ASRock may produce an opposite problem in some cases, as it sits much nearer to the top side of the board (not an issue in a Bitfenix Prodigy, might be an issue in a Xigmatek Aquila)

I'd probably go for a different PSU. I'd buy a Superflower made EVGA PSU in a heartbeat, but the lower wattage ones aren't necessarily as good, especially with that handle sticking out of the back. The XFX XTR is similarly priced so I'd probably grab one of those. There's also a few offerings from Seasonic, the Corsair HX650 and Rosewill Capstones.

Otherwise, your build is basically fine. If I was building a gaming machine for that display resolution, I'd probably want to go further into graphics, as a 2Gb card, even one as good as a GTX770, is going to have issues in the medium-term with demanding games. If you just want to play Diablo though, then it shouldn't really matter too much.
An alternate build might be to get a cheaper i5 (or Xeon E3 if your statistical analysis benefits from extra threads), decent non-overclocking board, basic CPU cooler, and push some more funds into graphics for either a GTX780 or R9 290 which are likely to be a bit more comfortable at 3440x1440.