PCPartPicker part list:
http://uk.pcpartpicker.com/p/1SoH6
Price breakdown by merchant: http://uk.pcpartpicker.com/p/1SoH6/by_merchant/
Benchmarks: http://uk.pcpartpicker.com/p/1SoH6/benchmarks/
CPU: AMD FX-6300 3.5GHz 6-Core Processor (£84.65 @ Amazon UK)
Motherboard: Asus M5A97 LE R2.0 ATX AM3+ Motherboard (£54.84 @ CCL Computers)
Memory: G.Skill Ripjaws X Series 8GB (2 x 4GB) DDR3-1600 Memory (£59.99 @ Amazon UK)
Storage: Hitachi Ultrastar 1TB 3.5" 7200RPM Internal Hard Drive (£35.99 @ Aria PC)
Video Card: PowerColor Radeon R9 270X 2GB Video Card (£144.99 @ Ebuyer)
Case: BitFenix Merc Alpha (Black) ATX Mid Tower Case (£32.90 @ Amazon UK)
Power Supply: XFX 550W 80 PLUS Bronze Certified ATX12V / EPS12V Power Supply (£49.93 @ CCL Computers)
Operating System: Microsoft Windows 7 Home Premium SP1 (OEM) (64-bit) (£65.99 @ Aria PC)
Monitor: BenQ GW2255 60Hz 21.5" Monitor (£90.59 @ Dabs)
Total: £619.87
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-10-23 23:24 BST+0100)