You can take this as a suggestion, I left space to add a more expensive GPU if you end choosing one but, for 1080p gaming, I still think the 280X is enough.
PCPartPicker part list:
http://uk.pcpartpicker.com/p/1Ryba
Price breakdown by merchant: http://uk.pcpartpicker.com/p/1Ryba/by_merchant/
Benchmarks: http://uk.pcpartpicker.com/p/1Ryba/benchmarks/
CPU: Intel Core i5-4670K 3.4GHz Quad-Core Processor (£167.99 @ Aria PC)
CPU Cooler: Cooler Master Hyper 212 EVO 82.9 CFM Sleeve Bearing CPU Cooler (£23.98 @ Scan.co.uk)
Motherboard: Gigabyte GA-Z87-HD3 ATX LGA1150 Motherboard (£87.14 @ Amazon UK)
Memory: G.Skill Ripjaws X Series 8GB (2 x 4GB) DDR3-1600 Memory (£59.99 @ Amazon UK)
Storage: Samsung 840 EVO 250GB 2.5" Solid State Disk (£128.50 @ Amazon UK)
Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive (£47.38 @ CCL Computers)
Video Card: Gigabyte Radeon R9 280X 3GB Video Card (£235.68 @ Dabs)
Case: Corsair 300R ATX Mid Tower Case (£60.06 @ Amazon UK)
Power Supply: SeaSonic G 550W 80 PLUS Gold Certified ATX12V / EPS12V Power Supply (£71.94 @ Scan.co.uk)
Optical Drive: Samsung SH-224DB/BEBE DVD/CD Writer (£12.38 @ Amazon UK)
Operating System: Microsoft Windows 7 Home Premium SP1 (OEM) (64-bit) (£67.19 @ Aria PC)
Total: £962.23
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-10-21 21:31 BST+0100)