Basically, what you DONT need are any drives and add-PCI cards (sound).
I agree with the above posters, but will say (1) I hook up my keyboard, so I can navigate BIOS and don't get the halt on keyboard error, (2) sorry if this sounds obvious, but when they say cpu they definately mean the heatsink and fan too (just being careful/sure there's no misunderstanding)
Fern