I wanted a nice setup to play back on PC, and to enjoy Elite: Dangerous in 21:9 1440p ;)
Here's the build I just did: I was aiming for a mATX SLI of 970s with a Corsair 350D, but all the Z97 boards were featuring card slots that were too close, and my 970s were touching each other.
I looked around, and found out that the NZXT S340 was almost as small as the 350D, by giving up on the usual (and useless for me) drive bays. So I blessed NZXT and switched by to usual ATX, and now my 970s can breath =)
Props to Amazon Prime, I bought almost everything I could there as the return is so easy and convenient. As soon as I wanted to replace my mATX stuff with ATX, they just sent me the replacement parts right away. Same for the screen, which arrived broken.
Also the LG 34UC97-S screen is great as it acts as a KVM: The screen makes it easy to keep the same keyboard/mouse/headphones with both a mac and a PC by switching between Thunderbolt and DisplayPort/USB inputs.
Update: I refined the build: upgraded my SLI to 2 980 TIs, replaced my keyboard and mouse by SteelSeries, and added a 1TB SSD.