Just to give you another option this is probably what I'd choose going on the information you have given so far. It should be cheaper or on a par plus it includes Vista which, as was pointed out is necessary for 4gb of Ram or over (with a 32bit OS you will only see somewhere around 3.5gb).
Noctua NH-U12F (Socket LGA775/754/939/940/AM2) Heatsink £27.99
(£32.89) £27.99
(£32.89)
Samsung SH-183LBEBN 18x18 DVD±RW Dual Layer Serial ATA Lightscribe ReWriter (Black) - OEM £16.99
(£19.96) £16.99
(£19.96)
Western Digital Caviar SE16 320GB 3200AAKS SATA-II 16MB Cache - OEM £48.99
(£57.56) £97.98
(£115.12)
BFG GeForce 8800 GTX OC 768MB GDDR3 HDTV/Dual DVI (PCI-Express) - Retail £314.99
(£370.11) £314.99
(£370.11)
Gigabyte GA_965P_DS3P (Socket 775) PCI-Express DDR2 Motherboard £69.99
(£82.24) £69.99
(£82.24)
Intel Core 2 Quad Pro Q6600 "LGA775 Kentsfield" 2.40GHz (1066FSB) - Retail £291.99
(£343.09) £291.99
(£343.09)
Corsair HX 620W ATX2.2 Modular SLI Compliant PSU (CMPSU-620HXUK) £84.99
(£99.86) £84.99
(£99.86)
Lian Li PC-A16B Aluminium Full-Tower - Black £99.99
(£117.49) £99.99
(£117.49)
Microsoft Windows Vista Home Premium 64-Bit Edition DVD - OEM - 1Pk (66I-00788) £63.99
(£75.19) £63.99
(£75.19)
OCZ 4GB (2 x 2GB) PC2-5400C5 Dual Channel Vista Upgrade Gold Series DDR2 (OCZ2VU6674GK) £114.99
(£135.11) £114.99
(£135.11)
Sub Total : £1,183.89
Shipping cost assumes delivery to UK Mainland with:
City Link Parcel Next Day (Delivered Mon-Fri)
(This can be changed during checkout) Shipping : £12.95
VAT is being charged at 17.5% VAT : £209.45
Total : £1,406.29