I'd probably opt for something like this, you get maybe 90% of the performance at stock speeds and you have the potential to overclock to easily make up the difference yet it only costs about 60% of the budget and that is without even taking into account the proposed price drops.
Corsair HX 620W ATX2.2 Modular SLI Compliant PSU (CMPSU-620HXUK) £74.99
(£88.11) £74.99
(£88.11)
Antec P182 Super Midi Tower Case - No PSU (Gun Metal Black) £69.99
(£82.24) £69.99
(£82.24)
OCZ 4GB (2 x 2GB) PC2-5400C5 Dual Channel Vista Upgrade Gold Series DDR2 (OCZ2VU6674GK) £89.99
(£105.74) £89.99
(£105.74)
Corsair HX 520W ATX2.2 Modular SLI Compliant PSU (CMPSU-520HXUK) £54.99
(£64.61) £54.99
(£64.61)
Gigabyte GA_P35C_DS3R (Socket 775) PCI-Express DDR2 & DDR3 Motherboard £79.99
(£93.99) £79.99
(£93.99)
BFG GeForce 8800 GTX OC 768MB GDDR3 HDTV/Dual DVI (PCI-Express) - Retail £314.99
(£370.11) £314.99
(£370.11)
Intel Core 2 Quad Pro Q6600 "LGA775 Kentsfield" 2.40GHz (1066FSB) - Retail £199.99
(£234.99) £199.99
(£234.99)
Optiarc NEC AD7170S Serial ATA 18x18 DVD±RW Dual Layer ReWriter (Black) - OEM £16.99
(£19.96) £16.99
(£19.96)
Western Digital Caviar SE16 320GB 3200AAKS SATA-II 16MB Cache - OEM £45.99
(£54.04) £45.99
(£54.04)
Noctua NH-U12F (Socket LGA775/754/939/940/AM2) Heatsink £32.99
(£38.76) £32.99
(£38.76)
Sub Total : £980.90
Shipping cost assumes delivery to UK Mainland with:
City Link Parcel Next Day (Delivered Mon-Fri)
(This can be changed during checkout) Shipping : £14.95
VAT is being charged at 17.5% VAT : £174.27
Total : £1,170.12