PCPartPicker part list:
http://uk.pcpartpicker.com/p/1y3IQ
Price breakdown by merchant: http://uk.pcpartpicker.com/p/1y3IQ/by_merchant/
Benchmarks: http://uk.pcpartpicker.com/p/1y3IQ/benchmarks/
CPU: AMD FX-6300 3.5GHz 6-Core Processor (£85.99 @ Aria PC)
Motherboard: ASRock 970 PRO3 R2.0 ATX AM3+ Motherboard (£53.78 @ Amazon UK)
Memory: Kingston Blu Red Series 8GB (2 x 4GB) DDR3-1333 Memory (£50.15 @ Amazon UK)
Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive (£48.36 @ CCL Computers)
Video Card: MSI Radeon HD 7850 2GB Video Card (£125.37 @ Dabs)
Power Supply: XFX 550W 80 PLUS Bronze Certified ATX12V / EPS12V Power Supply (£49.86 @ Scan.co.uk)
Optical Drive: LG GH24NS95 DVD/CD Writer (£14.99 @ Amazon UK)
Total: £428.50
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-08-30 21:12 BST+0100)