Well up to £600 inc VAT and delivery at a push: 
  
The Dell offer was: 
  
AMD 64 X2 Dual Core 5600+ 
Vista Home Premium 
2GB RAM 
20" Wide Flat Panel 
500GB SATA HDD 
256MB ATI Radion 
was £569 inc VAT and shipping 
  
I was really surprised at what you can now get for the money, as I havent really looked at PC specs in the last couple of years. 
  
Unfortunately today its gone up back to £649, but I have a mate who's other half can get a discount on Dell so Im exploring that avenue at the moment....... 
  
GET A MAC MINI   MUCH BETTER