I love my mITX PC. I built mine primarily as a HTPC, and light gaming rig. I was in a small condo at the time, so space was prudent, and going mitx filled all the needs perfectly. I was using the built in wifi for the first year or so, which was fine, and now that Ive moved somewhere larger, the pc sits inside my tv stand and Im using ethernet.
I have since upgraded the GPU to handle 1080p60 in most titles (CPU being the limiting factor)
Mine is a Fractal Design Node 304, so I have room for a full length GPU (MSI rx 470 Gaming X) and room for a full height cpu cooler. I can have up to 6 HDDs, or remove cages down tomy current 2 (1 HDD, 1 SSD)
Core i3 4150 (stock cooler,because its an i3)
rx 470 4GB
8GB RAM
2 TB HDD, 120GB SSD
450W semi modular PSU