Gaming / multitasking rig

[HSK]

Hi guys, I posted a while back for some helping on spec'ing a PC - I want to use it for more gaming (2560x1440) now, and overclocking / multitasking etc.

Been looking at this:-

PCPartPicker part list: http://uk.pcpartpicker.com/p/1OM0B
Price breakdown by merchant: http://uk.pcpartpicker.com/p/1OM0B/by_merchant/
Benchmarks: http://uk.pcpartpicker.com/p/1OM0B/benchmarks/

CPU: Intel Core i7-4770K 3.5GHz Quad-Core Processor (£245.99 @ Aria PC)
CPU Cooler: Corsair H100i 77.0 CFM Liquid CPU Cooler (£90.41 @ Aria PC)

Motherboard: Gigabyte GA-Z87X-D3H ATX LGA1150 Motherboard (£109.04 @ Scan.co.uk)
OR
Motherboard: Gigabyte GA-Z87X-UD4H ATX LGA1150 Motherboard (£144.05 @ Amazon UK)

Memory: Corsair Vengeance Pro 8GB (2 x 4GB) DDR3-1866 Memory (£69.98 @ Amazon UK)
Memory: Corsair Vengeance Pro 8GB (2 x 4GB) DDR3-1866 Memory (£71.99 @ Amazon UK)
Storage: Samsung 840 Pro Series 256GB 2.5" Solid State Disk (£163.79 @ Aria PC)
Storage: Seagate Barracuda 2TB 3.5" 7200RPM Internal Hard Drive (£63.37 @ CCL Computers)
Storage: Seagate Barracuda 2TB 3.5" 7200RPM Internal Hard Drive (£63.37 @ CCL Computers)
Video Card: EVGA GeForce GTX 780 3GB Video Card (£508.79 @ Aria PC)
Case: Corsair 600T ATX Mid Tower Case (£149.52 @ Scan.co.uk)
Power Supply: Be Quiet POWER ZONE 650W 80 PLUS Bronze Certified ATX12V / EPS12V Power Supply (£84.99 @ Ebuyer)

Total: £1621.24 or Total: £1656.25

Any suggestions on this would be a great help.

[TheDutyPaid]

eBuyer has the Corsair 750W CXM Builder Modular 80+ Bronze PSU for £74.99 at the moment, a £10 saving.

Would it be a better idea to get 16GB of RAM on a 2X8GB kit?