PCPartPicker part list:
http://uk.pcpartpicker.com/p/sBDTgs
Price breakdown by merchant: http://uk.pcpartpicker.com/p/sBDTgs/by_merchant/
CPU: Intel Core i5-4460 3.2GHz Quad-Core Processor (£139.67 @ CCL Computers)
Motherboard: Gigabyte GA-H97M-D3H Micro ATX LGA1150 Motherboard (£69.00 @ Aria PC)
Memory: Corsair Vengeance 8GB (2 x 4GB) DDR3-1600 Memory (£40.88 @ Aria PC)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive (£32.40 @ Aria PC)
Video Card: MSI GeForce GTX 980 4GB Twin Frozr Video Card (£389.99 @ Amazon UK)
Case: Zalman Z11 Plus ATX Mid Tower Case (Purchased For $0.00)
Power Supply: XFX TS 650W 80+ Gold Certified ATX Power Supply (£57.07 @ More Computers)
Total: £729.01
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-07-08 18:20 BST+0100
here is what i would get in that price range.
this will play any game you throw at it at ultra, most games at ultra 1440p
You should definitely overclock the GPU though.
If you really want to game you could upgrade to a gtx 980ti.