I just upgraded my primary rig to Coffee Lake, which you can see at the Completed Build page here, so I had a bunch of unused parts lying around. So I spent about $230 to get another build up and running. It'll be primarily used as a server for my Plex server and Minecraft server, but I threw my GTX 770 in there so it's also capable of being a LAN rig that's easy to take somewhere. I always wanted to build a small form factor PC as well, so this was a fun side project alongside my Coffee Lake upgrade.
I'll go over the parts here:
CPU: My desktop's old Intel Core i5-2500K. Can't overclock it because I couldn't find a Mini-ITX Z68/Z77 motherboard, but I wasn't looking to overclock anyways so I'm not worried.
Cooler: My stock Intel cooler the 2500K came with is in pretty rough shape, so I got a Cryorig C7 to use instead. I had lots of worries about how it would fit because of where the CPU socket is on this motherboard, but everything fit just fine. It runs fairly quiet as well.
Motherboard: I actually bought this Asus P8H61-I R2.0 almost two years ago because I knew stores would be running out of Mini-ITX LGA 1155 motherboards. Glad I did because you can't really find new ones nowadays. I just needed a pretty barebones motherboard.
RAM: I actually salvaged this RAM out of some old systems and sold the RAM I had previously bought. This RAM works perfectly too, so can't complain there.
Storage: Paired my first SSD (purchased almost four years ago) with a HDD I salvaged out of a laptop. Tight fit since this case only holds two 2.5" drives (no 3.5" drives fit). I store all of my Plex media on the HDD.
Video Card: This MSI GTX 770 was what I used to use in my primary rig, so it's been sitting in its box waiting to be used again for about 6 months. It's a fairly big card, but it fits nicely in this case. If it gets hot, I can always add two 120mm fans right below the card.
Case: The Fractal Design Node 202 is an awesome case. Great form factor, great build quality. Highly recommend for people wanting a SFF machine.
OS: My old system's copy of Windows 10 Pro transferred over flawlessly since it was attached to my Microsoft account. So glad this is a feature now.
Other: The USB wireless adapter is a "just in case" thing, since I keep the system hooked up to Ethernet. The monitor is salvaged from an old desktop, which is fine since I mostly remote into this machine anyways. The Dell keyboard is also salvaged, but I love these things. For membrane keyboards, they're very satisfying to type on. I had the Mionix NAOS 7000 before I upgraded to a Logitech G502, so now the Mionix lives with the server.
This was a super fun project, and the finished product is really cool. Feel free to ask any questions!