This is the one I came up with.
PCPartPicker part list:
http://pcpartpicker.com/p/NJw4ZL
Price breakdown by merchant: http://pcpartpicker.com/p/NJw4ZL/by_merchant/
CPU: AMD FX-6300 3.5GHz 6-Core Processor ($109.99 @ NCIX US)
Motherboard: Gigabyte GA-970A-UD3P ATX AM3+ Motherboard ($84.99 @ Amazon)
Memory: PNY Optima 8GB (2 x 4GB) DDR3-1333 Memory ($69.99 @ Amazon)
Storage: Western Digital RE3 1TB 3.5" 7200RPM Internal Hard Drive ($47.49 @ Amazon)
Video Card: Gigabyte Radeon R9 280X 3GB WINDFORCE Video Card ($283.98 @ SuperBiiz)
Case: BitFenix Comrade ATX Mid Tower Case ($34.99 @ NCIX US)
Power Supply: Antec 450W ATX Power Supply ($37.00 @ Amazon)
Wireless Network Adapter: Rosewill RNX-N150UBE 802.11b/g/n USB 2.0 Wi-Fi Adapter ($11.99 @ Amazon)
Total: $680.42
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2014-08-26 11:04 EDT-0400
I would not reccomend skimping on a keyboard simply because it would either mean non-cherry switches, which are usually bad, or bad quality. The cheapest one I would recommend is this one:
http://www.ncixus.com/products/?usaffiliateid=1000031504&sku=67069&vpn=SGK-4000-GKCL1-US&manufacture=COOLERMASTER