These are the parts I used in my last 2 builds, one for my GF, the other for my workbench machine. The only difference is that in hers I used a motherboard with 802.11bgn, and mine just has GigE, and hers has a step lower processor. Neither had a video card, and instead of the 16GB I have in my current desktop, these only have 8GB each. They are also Mini-ITS size, small little cubes. They aren't going to be overclocked, so no need for a higher end chipset, and they will never have video cards added, again no need for the higher end chipset that supports multiple video cards. And no need for a third party fan, the stock Intel fans are MORE than sufficient for the modern low power processors.
MB: Asrock H110M-ITX (H110M-ITX/ac on hers)
Case: DIYPC HTPC-Cube
Power Supply: Seasonic G Series SSR-550RM (here I did not skimp, Seasonic is definitely a top tier brand, 5 year warranty, 80 Plus Gold, and modular)
CPU: In mine, an I3-6300, in hers, an I3-6100
Memory: Whatever DDR4 2133 was cheapest at the time, in my case GSkill NT Series 8GB (4GB x2)
Mine has a Samsung 850 Evo 500GB, hers has an 850 Evo 250GB. I've been using only Samsung SSDs in all my computers.
The performance is quite good, even in the 3D view of my model railroad CAD program (which I also drew my workbench design in) - on mine running at 2560x1440. The built in graphics from Intel has become MUCH better over the years.
Plenty of USB ports to plug my stuff in.