Here you go mate, this spec is brilliant for the money:
Western Digital Caviar Special Edition 160GB 1600AAJS SATA-II 8MB Cache - OEM
(£35.24) £29.99
Samsung SH-S203BEBN 20x20 DVD±RW Dual Layer Serial ATA ReWriter (Black) - OEM
(£18.79) £15.99
Gigabyte GA_P35_DS3R (Socket 775) PCI-Express DDR2 Motherboard
(£93.99) £79.99
EVGA GeForce 8800 GTS 320MB GDDR3 HDTV/Dual DVI (PCI-Express) - Retail (320-P2-E811-AR)
(£187.99) £159.99
Microsoft Windows Vista Home Premium 64-Bit Edition DVD - OEM - 1Pk
(£70.49) £59.99
LG L204WT 20" Widescreen LCD Monitor - Black
(£170.36) £144.99
Logitech Cordless Desktop S 510 - Retail
(£35.24) £29.99
Corsair HX 520W ATX2.2 Modular SLI Compliant PSU
(£72.84) £61.99
Lian-Li PC-7 PLUS Aluminium Midi-Tower Case - Silver
(£58.74) £49.99
Arctic Cooling Freezer 7 Pro CPU Cooler (Socket 775)
(£17.61) £14.99
Crucial Ballistix 2GB (2x1GB) DDR2 PC2-5300C3 667MHz Dual Channel Kit
(£64.61) £54.99
Intel Core 2 Duo E2160 "LGA775 Conroe" 1.80GHz
(£61.09) £51.99
Sub Total : £754.88
Shipping : £14.95
VAT : £134.72
Total : £904.55
Firstly, the 160GB is Western Digital, so very fast and reliable. A decent SATA DVD drive, nothing special there. The motherboard is based on the new 'P35' chipset, and so will be compatible with the new Intel 'Penryn' CPU's arriving early next year. The Graphics card is brilliant, much better than the ATI 2600 series, which aren't actually that good. I've included 64Bit Vista as it offers future compatibility, and many of the issues have been ironed out now. The monitor is 20" as requested, and is a decent LG panel. Included a decent Logitech Keyboard/Mouse combination. The Corsair PSU is the best around at the moment, and will handle anything for the next few years. The case is the best for the money and offers very good cooling and build quality. CPU cooler is very good and will allow you to overclock. The RAM is again, probably the best around and is very highly clockable. The CPU is a Core 2 Duo, and when overclocked can perform very nearly as well as the more expensive E6600. Enjoy mate.