The motherboard and CPU you have selected are fantastic; for building a workstation with ECC memory support that can leverage 8 slow cores well.
For gaming, you'd be much better off with a haswell i5. The to-the-door price of an i5-4440 + BIOSTAR Hi-Fi H81S2 would actually be less than the 8320 + M5A97. Gaming performance would be up to 40% better.
The PSU is mediocre quality but functional. The way I like to describe the EVGA B series, is that they are what people who can't be bothered to do their research buy from Best Buy at 6:30PM on a whim because they just want to get a machine up and working. If you're here asking questions, then that is evidence to support that you are interested in something better than "average joes run of the mill" PSU. A PSU with a smaller wattage rating, higher efficiency, higher thermal tolerances,, built from higher quality parts, is actually preferable and will cost about the same... The Rosewill Capstone 450W is the go-to PSU in this price class for people "in-the-know" about this stuff. The 450W size would be more than adequate for an i5 + R9 270X.