Yep, unless you already have them, it looks that way to me also. Seems that you'd have to add a CPU, OS ($ if Vista/XP, free if Ubuntu), keyboard and mouse.
But Jon covered the hard part.
Unless I'm missing something, these additions are easy to pick, and the motherboard should have information about which CPUs it supports.
One thing that I learned was that Vista has OEM and retail versions. I think you cannot move the OEM version to another computer, nor do you get support.