Home energy monitoring made easy is one of the holy grails for product designers these days (along with, for some reason, tree houses and spoke-less bikes). If it's too complicated to design energy-efficient appliances, we might as well make it easier to see how much power they're wasting. (That's called treating the symptom.)
Still, the trend has given us some provocative (or loony) options for whenever you get around to re-wiring your house. There's the Truepower U-Socket, for instance, which incorporates a pair of USB ports right into the outlet. It's designed so those ports don't act like energy vampires--the transformers needed to convert wall-socket electricity to 5V USB power are only turned on when you plug something in.
RISD student Conor Klein's Outlet Regulator spits itself out of the wall when it's done charging the gadget you've plugged in. It was modeled after a leech--yum! There are a couple other outlets that shut themselves off when they're done charging, but this one is nice and bitchy about it.
Gilles Belley's Energy Saver is a desk-mounted power strip of outlets that glow blue to visualize the energy your electronics drain when they're plugged in but not doing anything. Belley has a couple other riffs on that idea, including an Electrical Semaphore that glows orange during hours of peak energy use so you know to limit your power drain.