Nice choice on PSU
This is what I would do, brought from overclockers.co.uk
DFI LanParty UT NF4 SLI-D (Socket 939) PCI-Express Motherboard (MB-013-DF)
£102.50 £102.50
OCZ 1GB (2 x 512MB) PC3200 Dual Channel Platinum Series EL-DDR REVISION 2 CAS2 (MY-048-OC)
£139.95 £139.95
Seagate Barracuda 7200.7 Plus NCQ 160GB ST3160827AS SATA 8MB Cache - OEM (HD-015-SE)
£53.75 £107.50
NEC ND3540 16x16 DVD±RW Dual Layer ReWriter (Black) - OEM (CD-019-NE)
£26.80 £26.80
Antec TruePower 2.0 550W PSU (CA-028-AN)
£79.95 £79.95
Leadtek WinFast GeForce 6800 Ultra 256MB DDR3 TV-Out/Dual DVI (PCI-Express) - Retail (GX-055-LT)
£209.95 £209.95
AMD Athlon 64 3700+ San Diego 90nm (Socket 939) - Retail (ADA3700BNBOX) (CP-121-AM)
£164.95 £164.95
Subtotal £831.60
VAT £145.53
Total £977.13
I have left out the case, as that is your choice, as you know what you like in a case. If you want to save a few pounds, the 6800gt is a little less, but with such a small price difference the ultra was a bargain. The HDD are to be put in RAID0 for extra speed. If you don't overclock, than you may as well get value RAM, and you could bump it up to 2gb's as that will come to about the same price.