For an amd buld you could look at something like this,
PCPartPicker part list:
http://pcpartpicker.com/p/1XVNm
Price breakdown by merchant: http://pcpartpicker.com/p/1XVNm/by_merchant/
Benchmarks: http://pcpartpicker.com/p/1XVNm/benchmarks/
CPU: AMD FX-8320 3.5GHz 8-Core Processor ($158.98 @ SuperBiiz)
CPU Cooler: Corsair H60 54.0 CFM Liquid CPU Cooler ($49.99 @ NCIX US)
Motherboard: Gigabyte GA-990FXA-UD3 ATX AM3+ Motherboard ($125.98 @ SuperBiiz)
Memory: G.Skill Ripjaws X Series 8GB (2 x 4GB) DDR3-1600 Memory ($63.75 @ Newegg)
Storage: Kingston SSDNow V300 Series 60GB 2.5" Solid State Disk ($62.99 @ Adorama)
Video Card: Gigabyte Radeon R9 280X 3GB Video Card ($299.99 @ Amazon)
Power Supply: EVGA SuperNOVA NEX750B BRONZE 750W 80 PLUS Bronze Certified ATX12V / EPS12V Power Supply ($66.66 @ Newegg)
Optical Drive: LG GH24NS95 DVD/CD Writer ($15.99 @ Microcenter)
Operating System: Microsoft Windows 7 Home Premium SP1 (OEM) (64-bit) ($84.99 @ NCIX US)
Keyboard: Razer DeathStalker Wired Gaming Keyboard ($75.99 @ B&H)
Mouse: Razer Naga 2012 Wired Laser Mouse ($60.75 @ Amazon)
Headphones: Razer Kraken Pro Headset ($65.99 @ B&H)
Other: battlefield 4 ($59.99)
Total: $1183.05
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-11-05 17:20 EST-0500)
I chose the FX 8320 because of the price and with some overclocking it should do very well or even without that it should be good.
If you would choose the next cooler you could shave another $20 of,
http://pcpartpicker.com/part/cooler-master-cpu-cooler-rr212e20pkr2