Had a new machine last week, brand new from a UK seller on ebay.

Intel i7 920 (not overclocked yet)
Asus p6t SE motherboard
6GB DDR3 1666mhz corsair ram (3x2GB)
500GB HD
ATI HD4350
basic case and DVD writer

£545 delivered

I installed Windows 7 64bit. Been playing with Revit 2011 on it, very pleased with the spec and performance at the price.