1) You should get the Z97 instead the Z87, but it is up to you. 2) Also you can get the win7 pro for less too. 3) If you want you can get the 1600mhz ram, but the haswell likes the high speed ram.
Here is my list.
PCPartPicker part list:
http://uk.pcpartpicker.com/p/3HT66h
Price breakdown by merchant: http://uk.pcpartpicker.com/p/3HT66h/by_merchant/
Benchmarks: http://uk.pcpartpicker.com/p/3HT66h/benchmarks/
CPU: Intel Core i5-4670K 3.4GHz Quad-Core Processor (£155.99 @ Aria PC)
Motherboard: Gigabyte GA-Z97X-SLI ATX LGA1150 Motherboard (£97.49 @ Ebuyer)
Memory: G.Skill Ripjaws X Series 16GB (2 x 8GB) DDR3-1866 Memory (£116.99 @ Aria PC)
Storage: Crucial M500 120GB 2.5" Solid State Drive (£50.15 @ Amazon UK)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive (£35.94 @ Aria PC)
Video Card: MSI Radeon R9 280X 3GB TWIN FROZR Video Card (£204.34 @ Scan.co.uk)
Power Supply: XFX 650W 80+ Bronze Certified Semi-Modular ATX Power Supply (£62.69 @ CCL Computers)
Operating System: Microsoft Windows 8.1 (OEM) (64-bit) (£79.99 @ Amazon UK)
Total: £803.58
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2014-05-31 20:41 BST+0100)