Good build. Here are a few observations:
- PSU: For a few extra bucks, I would get something in the HX series because not only they're higher quality but most of all they're modular (meaning less cables laying around in your case). Also 850-Watt seems a little overkill for your setup, so you could settle for a HX750 for example.
- HDD: Now I understand you have a budget limit, but video editing requires a lot of writing to the disk. Something like 2 x WD 1TB "Red" in Raid 0 would be better suited for video editing. Or one single large SSD, they make 1TB SSD now but I know they're expensive, you could check 512GB models instead, but yeah still expensive, lol.