This is my first build, with video editing as its primary purpose, and gaming secondary (hence the balance of the CPU and graphics card).
Ryzen 5 1600 (OC'd to 3.7 GHz): Ryzen was the obvious choice when I bought parts given its multicore speeds. I initially planned to buy a Ryzen 7 and repurpose an old GT 220 in the short term, but I decided that a bit of balance would be a good idea. Video editing is very smooth on this, though I occasionally have to turn the preview down to 1/2 or 1/4 quality depending on what effects I have active. It hasn't been a bottleneck for gaming since I tend to play less intensive games.
MSI B350 Tomahawk: I wanted to go with a full ATX board for its PCI-e slots. At first I planned on going with the MSI B350 PC Mate since it's essentially the same as the Tomahawk besides aesthetics (and I didn't want a case with a side panel window), but costs less. It turned out that it's functionally the same price for me because of merchant availability and shipping charges, so I went with the Tomahawk since it was available locally and I prefer to deal with warranty issues in person. I had the usual Ryzen chipset issues at first but after a BIOS flash, it's functioning perfectly.
Corsair Vengeance LPX 8GB: I initially intended on installing 16GB, and still plan on doing so, but I've found 8GB to be reasonably sufficient so far. This 3000 MHz kit was cheaper than the equivalent 2400 kit for some reason, and it's overclocked to 2933 MHz without issue.
Samsung 960 EVO 250GB: Boot drive. A bit over the top, but useful in editing large video files. This is the first PC I've had that's actually booted from an SSD, so it's pretty neat.
1TB WD Green drives: I had these lying around.
GTX 1050: Most of the games I play run at ultra settings, at a smooth 60FPS at 1080p with this card. I considered buying a 1050 Ti over this, but this has a very solid build quality and the only Tis at reasonably comparable prices do not. A key consideration for this part was dual monitor support for my editing workspace, and this card's 3 HDMI outs makes it very suitable, another advantage of this card over some of the low-end 1050 Tis. It's also better than than the old GT 220...
Corsair Carbide 100R Silent Edition: I'm very happy with all my decisions to this point, but the 100R Silent edition is an exception. Not that I don't like it - it's pretty sleek and does what it needs to do, but has insufficient cable management space (I have to force the back panel on), and rubber grommets on the cable management holes would be nice. I will definitely look to something a bit roomier in future (though this is the first time I've really done cable management inside a PC, so my inexperience may have made the problem worse).
Corsair CX500 PSU: I do regret this decision, though the PSU performs fine. Had I known how little the cable sleeves do to improve aesthetics, I would have spent more to get something semi-modular with black cables. Not that it matters too much since the case has no window, but it bugs me knowing that the cables look like that inside. That said, it was at a good price and has kept my system running perfectly, so it's not a big deal.
TP-Link 802.11n Wireles NIC: This isn't the best or fastest adapter out there, but the network it's connected to isn't the fastest either. It's functional.
To summarise, I'm pretty happy with the build overall, and it does its job well. My biggest issue is cable management, but I've learned my lesson on that front for future builds.