Windows 7 system builders edition?
 

I'm interested in getting windows 7, and have several other people in my family that want to do the same. Do I have to buy seperate cd's for each computer? Or is their some way I can get 3-5 installs out of one cd?

Thanks in advance

this is good for three PCs, its Home Premium and the upgrade version annoyingly enough but otherwise you are looking at the OEM version which is one disk, one computer

1 key per computer.

Are all these people in the same house? If so, you might be able to buy a technet subscription and go that route. Assuming you decided that you were the primary user of all PC's and you're only 'evaluating' Win7 on them all... You'd be walking a razor line of the EULA of technet though. And it wouldn't be within license agreement if your family's spread across several house holds.