@ Stokecity_m, I just went on overclockers for you and put a basket together from items they have in stock.
Intel Core i7 920 2.66Ghz (Nehalem) (Socket LGA1366) - Retail
http://www.overclockers.co.uk/showproduct.php?prodid=CP-252-IN
Asus P6T Intel X58 (Socket 1366) PCI-Express DDR3 Motherboard
Unfortunately the MSI board I would reccomend isn't in stock, and having nothing but bad experiences with gigabyte this is the best thing I think.
http://www.overclockers.co.uk/showproduct.php?prodid=MB-320-AS
EVGA GeForce 9800 GT 512MB GDDR3 TV-Out/Dual DVI (PCI-Express) - Retail (512-P3-N971-TR) Evga have a trade up program and a 10 year warrenty.
http://www.overclockers.co.uk/showproduct.php?prodid=GX-082-EA
Corsair TX 650W ATX2.2 SLi Compliant Power Supply
To power it all, a quality PSU is a must. (can be switched for another brand, but these seem pretty rock solid).
http://www.overclockers.co.uk/showproduct.php?prodid=CA-008-CS
Crucial 3GB DDR3 PC3-10666C9 1333MHz (3x1GB) Triple Channel Kit (CT3KIT12864BA1339)
3GB tripple channel ram to make the most of your I7's abilities. If your sticking with 32 bit then no point getting more, and no point getting faster as you wont be overclocking.
http://www.overclockers.co.uk/showproduct.php?prodid=MY-124-CR
All in all that comes to.
Sub Total : £584.91
Shipping : £8.99
VAT is being charged at 15% VAT : £89.09
Total : £682.99
Maybe higher than your willing to spend? Maybe not. But it will last you a good while, with upgradability with RAM if you go to 64 bit windows, an evga trade up program if you want a better gfx card in the future and rock solid PSU and motherboard to support it all.
If you want something cheaper, give me a better budget cost and I can tailor something down.