This is what I would do
PCPartPicker part list:
http://uk.pcpartpicker.com/p/3O4Ya
Price breakdown by merchant: http://uk.pcpartpicker.com/p/3O4Ya/by_merchant/
Benchmarks: http://uk.pcpartpicker.com/p/3O4Ya/benchmarks/
CPU: Intel Xeon E3-1230 V3 3.3GHz Quad-Core Processor (£176.39 @ Aria PC)
Motherboard: Gigabyte GA-H97-D3H ATX LGA1150 Motherboard (£79.25 @ Dabs)
Memory: G.Skill Ripjaws X Series 8GB (2 x 4GB) DDR3-1866 Memory (£63.51 @ Amazon UK)
Memory: Corsair Vengeance 8GB (2 x 4GB) DDR3-1600 Memory (£59.98 @ Amazon UK)
Storage: Crucial M500 120GB 2.5" Solid State Disk (£50.15 @ Amazon UK)
Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive (£34.45 @ Aria PC)
Video Card: MSI GeForce GTX 780 3GB TWIN FROZR Video Card (£349.99 @ Scan.co.uk)
Case: NZXT Phantom 630 (Gunmetal) ATX Full Tower Case (£89.59 @ Scan.co.uk)
Power Supply: XFX 650W 80+ Bronze Certified Semi-Modular ATX Power Supply (£62.69 @ CCL Computers)
Total: £966.00
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2014-05-21 06:47 BST+0100)