This concept Velcro wall socket seems like it would be a good idea on paper, seeing as it attaches Velcro to both the socket and AC adapters so you can keep them close when not in use. But in practice, the fact that you can keep a plug attached close to the wall, instead of on the floor, does very little to act "as a strong reminder to the user to unplug the plug," which would in turn save power. Unless you're really anal about how high your electric bill is, you're not going to be going around and unplugging your electronics after you use them.
Velcro Wall Socket Conserves Energy [Yanko Design]