I would recommend abit differet
AMD Athlon 64 4000 (Socket 939) £493.44
MSI K8N Neo4 Diamond nForce4 SLi (Socket 939) PCI-Express Motherboard £152.69
Corsair 1GB DDR XMS3200C2 Pro TwinX (2x512MB) CAS2 £170.32
MSI NX6800-TD256E GeForce 6800 256MB DDR TV-Out/DVI (PCI-Express) x2 £446.38
Seagate Barracuda 7200.7 200GB SATA 8MB Cache £82.19
Western Digital Raptor 36.7GB 10,000RPM SATA 8MB Cache £140.88
Sunbeam Transformer Gaming ATX Case - Blue £76.32
Antec TrueBlue 480W PSU £76.32
Akasa AK174CB-4BLB 120mm Blue LED fan 2 £23.38
total £1,661.92 plus shipping. Now this leaves money for a decent sound setup aswel as bits and peices like keyboard and laser mouse, artic silver 5 etc.
The reason ive got rid of the fx55 is i think the extra performance over the 4000 is not worth the extra cash and a sli 6800 would perform at better as it is a gaming machine. These prices are all from www.overclockers.co.uk
and ive had no problems ordering with my debit card from them and have done so many times. BUT if i was you i would really look into other sites aswel because im finding www.scan.co.uk
abit cheaper but it does not carry the range of parts you will want so consinder ordering from the 2 places. If you can possible get abit more cash the only way i would guess at improving this would be to up the graphics cards to 6800GTs but this is upto you becase it is easily and extra 100-150 but thats your choice.
Hope this helps