Dell currently offer a 20% off coupon on their business site.
Coupon code is : M1?3S7XDD0??T6
Valid from 20/01/2010 - 23/01/2010
Plus until 26/01/2010 they are offering additonal discounts and free delivery.
A base Vostro featuring a firstname.lastname@example.org QC, 3GB RAM, 500GB HD and ATI 4350 comes in at £497.26 inc VAT and delivery.
Upgrade RAM to 4GB (2x 2048) and add Logitech wireless desktop = £501.04 inc VAT and delivery.
You can pick up a slightly slower i5 Vostro for around £400 all in.
Looks like a good deal for a PC with the newer i5/i7 processors.