Went with an 80+ Bronze PSU to fit the budget, but this PSU is solid.
PCPartPicker part list / Price breakdown by merchant
| Type | Item | Price |
|---|---|---|
| CPU | AMD FX-6300 3.5GHz 6-Core Processor | $96.99 @ Amazon |
| Motherboard | Gigabyte GA-78LMT-USB3 Micro ATX AM3+ Motherboard | $58.99 @ Amazon |
| Memory | G.Skill Sniper Series 8GB (1 x 8GB) DDR3-1600 Memory | $60.98 @ Newegg |
| Storage | PNY Optima 240GB 2.5" Solid State Drive | $89.99 @ Amazon |
| Video Card | MSI Radeon R9 280 3GB TWIN FROZR Video Card | $189.99 @ Newegg |
| Case | Fractal Design Core 1300 MicroATX Mini Tower Case | $29.99 @ NCIX US |
| Power Supply | SeaSonic 620W 80+ Bronze Certified Fully-Modular ATX Power Supply | $54.99 @ Amazon |
| Total | ||
| Prices include shipping, taxes, and discounts when available | $581.92 | |
| Generated by PCPartPicker 2015-01-20 00:46 EST-0500 |
You have to go with a motherboard one generation old in order to get mATX with the FX-6300. I would consider going Intel. This will work though. You just don't have SATA III speeds for the SSD. Which is why I went with the cheapest 240GB.
Plenty of RAM with room to upgrade. Dual channel does basically nothing to improve gaming performance.
With this graphics card, you're going a little beyond "mid-range". So that's nice. One suggestion would be to not put the computer in a confined space where it won't get proper ventilation.