-Perhiperals-
Razer Copperhead Chaos Green 2000dpi High Precision Gaming Mouse - Retail
£27.99 (£32.89)VAT
Saitek PZ30AU Eclipse Illuminated Keyboard - Red
£21.99 (£25.84)VAT
-Case-
Lian-Li PC-7 PLUS Aluminium Midi-Tower Case - (Black or Silver your choice)
£49.99 (£58.74)VAT
-Hardware-
LiteON DH-20A1P-45C 20x DVD±RW x12 Ram Dual Layer DVD-Writer (Black) - OEM
£14.99 (£17.61)VAT
Samsung SpinPoint T HD501LJ 500GB SATA-II 16MB Cache - OEM
£59.99 (£70.49)VAT
BFG GeForce 8800 GTX OC 768MB GDDR3 HDTV/Dual DVI (PCI-Express) - Retail
£314.99 (£370.11)VAT
EVGA nForce 680 (Socket 775) PCI-Express DDR2 Motherboard
£144.99 (£170.36)VAT
Intel Core 2 Duo E6600 "LGA775 Conroe" 2.40GHz (1066FSB) - Retail
£127.99 (£150.39)VAT
Crucial Ballistix 2GB (2x1GB) DDR2 PC2-6400C4 800MHz Dual Channel Kit (BL2KIT12864AA804)
£99.99 (£117.49)VAT
Corsair HX 520W ATX2.2 Modular SLI Compliant PSU (CMPSU-520HXUK)
£59.99 (£70.49)
-Cooling-
Scythe Infinity Heatpipe CPU Cooler (Socket 478, 775, AM2, 754, 939, 940)
£26.99(£31.71)VAT
Sub Total : £949.89
Shipping : £12.95
Vat : £168.50
Total : £1,131.34
Hope that helps, i included no sound card as the motherboard already has a good sound system built into it unless you are able to make audiable differances an X-FI card can be included at a later date, you can upgrade the a 620w if you plan on adding another GTX at a later date other than that if you stick with 1 beefy graphics card then 520w is fine.
If you want to cut the price down on the motherboard then go for a gigabyte DS3 which is a lot cheaper but wont support sli but is still an extremely good overclocker.
the case lian li is an excellent cooler with 2 120mm fans included for great cooling one of which is located at the front and one at the rear.
500gb hdd which you specified, really i dont know how you will use up all of that space unless you are encoding videos and such, if you are just going to be gaming i would down it along with the price for a 250gb hdd which another 250/320gb hdd can be added at a later date, and if you want a fast hdd then you can stripe one.
Core 2 duo because i know you are going to be using the pc for gaming, quad core is pointless unless you are utilising 4 monitors, video encoding or folding etc (also if you want the take a bit of the processor price you can get the e6420 which is the 2.13ghz version, overclocks very well)
I have an old version of the razer mouse (diamondback) and they are pretty solid mouses, i had no trouble installing drivers, included software and its still performing well after about 3 years, keyboard is really nice for the late night gaming sessions as the back of the keys are luminated so you know what you are pressing without having to tun on the lights (scary games

)
RAM is pretty solid best going atm for a good price, it can be changed for 5300 but this is still pretty solid ram, i use it and hasnt failed yet.
gl with whatever you choose, sinny. =)