What sort of budget have you got to play with firstly?
Could get one of the new cataclysm builds such as
this one, but not sure if thats a bit too much money, or if you built it yourself you could get a very similar system for marginally less
Radon Intel Core i5 760 2.80GHz @ 4.00GHz Overclocked Bundle - Gigabyte £389.99
OcUK Value GeForce GTX 460 1024MB GDDR5 PCI-Express Graphics Card £135.11
OCZ StealthXStream 2 600W Power Supply £59.98
Samsung SpinPoint F3 500GB SATA-II 16MB Cache - OEM (HD502HJ) £33.98
Coolermaster Elite 370 Case - Black £32.99
Samsung SH-S223C/BEBE 22x DVD±RW SATA ReWriter (Black) - OEM £12.91
Sub Total : £565.94
Shipping cost assumes delivery to UK Mainland with:
DPD Next Day Parcel
(This can be changed during checkout) Shipping : £11.25
VAT is being charged at 17.50% VAT : £101.01
Total : £678.20