I added up your totals, and done this build for you.
Your basketProduct Name Qty Price Line Total
Gainward GeForce GTX 580 "GOOD Edition" 1536MB GDDR5 PCI-Express Graphics Card £347.99
(£289.99) £347.99
(£289.99)
Intel Core i5-2500K 3.30GHz (Sandybridge) Socket LGA1155 Processor £161.99
(£134.99) £161.99
(£134.99)
Asus P8Z68-V Intel Z68 (Socket 1155) DDR3 Motherboard £130.00
(£108.33) £130.00
(£108.33)
XFX 850W Black Edition Modular Power Supply £122.99
(£102.49) £122.99
(£102.49)
Crucial RealSSD M4 64GB 2.5" SATA 6Gb/s Solid State Hard Drive £99.98
(£83.32) £99.98
(£83.32)
Fractal Design Define XL Full Tower Case - Black Pearl £89.99
(£74.99) £89.99
(£74.99)
Microsoft Windows 7 Bundle - Home Premium 64 Bit £68.40
(£57.00) £68.40
(£57.00)
Options applied to the above product:
Western Digital Caviar Blue 500GB SATA 6Gb/s 16MB Cache - OEM (WD5000AAKX) £32.99
(£27.49) £32.99
(£27.49)
Corsair XMS3 8GB (2x4GB) DDR3 PC3-12800C9 1600MHz Dual Channel Kit (CMX8GX3M2A1600C9) £64.99
(£54.16) £64.99
(£54.16)
Thermalright Silver Arrow CPU Cooler (Socket LGA1366/LGA1155/LGA1156/LGA775/AM2/AM3) £50.99
(£42.49) £50.99
(£42.49)
LG GH22NS70 22x DVD±RW SATA ReWriter (Black) - OEM £16.99
(£14.16) £16.99
(£14.16)
Sub Total : £989.41
Shipping cost assumes delivery to UK Mainland with:
DPD Next Day Parcel
(This can be changed during checkout) Shipping : £16.85
VAT is being charged at 20.00% VAT : £201.25
Total : £1,207.51
A 2500K is as fast as in gaming as a 2600K -
http://www.anandtech.com/bench/Product/288?vs=287
The Fractel XL Tower is only £5 more than a R3.
The XFX PSU I selected is good,
http://www.hardwaresecrets.com/article/808
http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story&reid=165
Also included the latest Z68 motherboard and a SSD