Looks really good Jabuuty. The FX-6100 is a great CPU for the price and the UD3 mobo is also very good. I do however suggest upping the PSU to around 650W, not because 520W isn't enough but just in case you make a new build a couple years down the track. You don't want to buy a new PSU in the future when you could have one that's capable now.
EVGA SuperNOVA NEX650G 650 Watt ATX 12V Power Supply 120-PG-0650-GR - Micro Center
EVGA are a solid brand and it's fully modular which is very handy for keeping your PC neat and tidy whilst maximizing airflow (not to mention it allows you to sleeve your own cables if you wish to go down that road).
Also recommend you grab an SSD whenever funds open up, probably one of the best upgrades anyone can do right now is put their OS on an SSD.