I have a few questions/comments:
So you are in CR but you have links for amazon.com, which is US only isn't it? I haven't looked into it too much.
Where are you able to buy parts, (websites), only amazon or newegg, tigerdirect, and such others?
The build you have:
-The WD Green has a slower RPM than a WD blue or black, I swapped it to a blue
-Kept the CPU
-The motherboard needs to be a "Z" series board so that you can overclock. You must have both a "K" series intel CPU and "Z" series motherboard to overclock. Swapped it for an MSI board.
-The GTX 660 is a bit old, try to fit in a GTX 760 or 770. I snuck in a GTX 770 but you may need to downgrade to a 760 if you want to save a few bucks. You also may need to do this if you need to purchase an OS and if you need an optical drive.
-Swapped the RAM to a popular G.Skill one but G.Skill, Corsair, and Kingston Fury series are all great RAM manufacturers.
-Swapped the PSU to a 550W XFX. your estimated wattage is 411W so you are well within that margin.
Here is a mock build of what parts you should pick. The case varies only your personal preference so if you don't like it just swap it out. Do try to find something with a top mounted fan at least as heat rises and blowing it out and up is very effective.
PCPartPicker part list /
Price breakdown by merchant
CPU: Intel Core i5-3570K 3.4GHz Quad-Core Processor (£162.60 @ Aria PC)
Motherboard: MSI Z77A-G43 ATX LGA1155 Motherboard (£65.99 @ Aria PC)
Memory: Corsair Vengeance 8GB (2 x 4GB) DDR3-1600 Memory (£55.34 @ Scan.co.uk)
Storage: Samsung 840 EVO 250GB 2.5" Solid State Drive (£91.99 @ Amazon UK)
Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive (£35.99 @ Aria PC)
Video Card: Asus GeForce GTX 770 2GB DirectCU II Video Card (£239.72 @ Scan.co.uk)
Case: NZXT Source 210 (Black) ATX Mid Tower Case (£35.96 @ Scan.co.uk)
Power Supply: XFX 550W 80+ Bronze Certified ATX Power Supply (£44.11 @ CCL Computers)
Total: £731.70
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2014-06-17 23:40 BST+0100