For around £1000 something like this would probably do as it gives a good base of components and pretty strong overall performance.
OCZ 4GB (2 x 2GB) PC2-5400C5 Dual Channel Vista Upgrade Gold Series DDR2 (OCZ2VU6674GK) £99.99
(£117.49) £99.99
(£117.49)
Intel Core 2 Quad Pro Q6600 "LGA775 Kentsfield" 2.40GHz (1066FSB) - Retail £149.99
(£176.24) £149.99
(£176.24)
Corsair HX 520W ATX2.2 Modular SLI Compliant PSU (CMPSU-520HXUK) £54.99
(£64.61) £54.99
(£64.61)
Akasa Eclipse 62 Aluminium Case - No PSU £73.99
(£86.94) £73.99
(£86.94)
NEC AD7170S Serial ATA 18x18 DVD±RW Dual Layer ReWriter (Black) - OEM £16.99
(£19.96) £16.99
(£19.96)
Tuniq Tower 120 CPU Cooler (Socket 478/754/939/940/AM2/LGA775) £26.99
(£31.71) £26.99
(£31.71)
Western Digital Caviar SE16 500GB 5000AAKS SATA-II 16MB Cache - OEM £56.99
(£66.96) £56.99
(£66.96)
BFG GeForce 8800 GTX OC 768MB GDDR3 HDTV/Dual DVI (PCI-Express) - Retail £294.99
(£346.61) £294.99
(£346.61)
Gigabyte GA_P35C_DS3R (Socket 775) PCI-Express DDR2 & DDR3 Motherboard £74.99
(£88.11) £74.99
(£88.11)
Sub Total : £849.91
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 : £151.00
Total : £1,013.86