This has been an ongoing project for a few months now. It started out as an mITX powerhouse with the 9900K + 2080 Ti, but as I ended up with an NH-D9L due to space constraints in the Corsair 250D case I had from an old HTPC, CPU temps were... not ideal to say the least (hit 110° at one point running Prime95). So I decided to move to mATX, which allowed me to squeeze an NH-D15S to cool the 8 power-hungry cores. Although interestingly enough the package power recorded by HWMonitor actually went down... a lot (220W to "just" 180W). As a result, load temps on P95 now sit around 85°, so much more manageable.
As for the GPU, it's an NVIDIA 2080 Ti FE. I considered a lot of the aftermarket cards, which certainly can hit higher clock speeds and run at lower temps, but I just didn't look the look of any of them. The Founders Edition cards just look so darn good without any unnecessary garnish I picked one up, and thankfully they're a little cheaper than most of the alternatives. Boost clocks still hit ~1800MHz, and 4K performance has been perfectly fine, so no complaints here.
The sound card is in there to pipe 5.1 audio to my Logitech Z-5500 surround system over a single optical audio cable. Since the on-board audio sadly doesn't support Dolby Digital Live or DTS Connect, I was forced to dig out my old Creative Zx card and pop it in there (another benefit of having moved to mATX).
Uses are primary 4K gaming and photo editing. Lightroom will pretty much eat up whatever resources you through its way (seriously, Chrome is nothing compared to anything made by Adobe).
Sleeved cables were made by Ensourced.net, and I couldn't be happier with them. Took a bit of work to get them to installed just right, but the end result was easily worth the effort.