The only problem might be if you try to use the wrong media. For XP, there were basically three general media versions: OEM, retail, VLK. For example, if you tried to use an OEM key with an install from VLK media, the install wouldn't take the key. It actually is a bit more complicated as I've seen things like Dell OEM keys not working with XP installs from HP OEM media as an example.
I am honestly not sure if this is something Microsoft continued in Vista and 7, but I wanted to let you know.