If you plan on overclocking or would like a somewhat quite machiene. I would consider a different motherboard, there are quite a few 9xx AM3+ around or below $100. I have that MB it came free with a purchase. Nothing wrong with it, it just isn't made for overclocking. FYI other than crossfine/PCI and possibly some extra bells and whistles there isn't really any difference between the 970 or 990's.
Also pick up an aftermarket cooler. Any of the 212's will be far superior to the boxed fan the 8320 comes with. I have an 8320 cooled by a 212 evo @4ghz 24/7 and it stays relatively cool.
Lastly, you may want to consider a bit more robust power supply. 450w doesn't get you very far.