£725. hmm. It's nice I guess. The board won't really be that oc'able. It's kinda weird. Spending £172 on a CPU, that has an unlockable multiplier than not buying an aftermarket solution and a decent motherboard. If I were you I'd look into the build below. It's slightly more expensive. But it has a better CPU for the price. Good OC potential.
And with mantle coming up soon, it has way more potential than the gtx 770. You could interchange them if you wanted.
PCPartPicker part list:
http://uk.pcpartpicker.com/p/2IW3d
Price breakdown by merchant: http://uk.pcpartpicker.com/p/2IW3d/by_merchant/
Benchmarks: http://uk.pcpartpicker.com/p/2IW3d/benchmarks/
CPU: AMD FX-8350 4.0GHz 8-Core Processor (£139.19 @ Aria PC)
CPU Cooler: Cooler Master Hyper 212 EVO 82.9 CFM Sleeve Bearing CPU Cooler (£25.18 @ Aria PC)
Motherboard: MSI 990FXA-GD80 ATX AM3+ Motherboard (£117.50 @ Ebuyer)
Memory: Patriot Viper 3 16GB (2 x 8GB) DDR3-1866 Memory (£117.59 @ Amazon UK)
Video Card: Gigabyte Radeon R9 280X 3GB Video Card (£224.48 @ Amazon UK)
Case: Fractal Design Define XL R2 (Black Pearl) ATX Full Tower Case (£100.99 @ Amazon UK)
Power Supply: Corsair Builder 750W 80+ Bronze Certified ATX Power Supply (£67.99 @ Dabs)
Total: £792.92
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2014-01-29 03:50 GMT+0000)