pollaxe
I got quite excited by this - until I saw the price. :(
The case is from AOpen - comes with the motherboard and external PSU … they go for around £200 if you can find one (much easier to get in the US).
Then it's just the CPU (£50 up), memory, CD and HDD (say £150-200 for 4GB, 320GB and a reasonable CPU) … reckon you could build a decent spec one for a chunk less than £500.