Wow, this is just awesome. Battery research has been neglected, relative to battery powered technology anyway. Someone needed to do something drastic, and its a clever move on Tesla's side to push to advance not only batteries for their vehicles (which has a very small market right now), but also for utility power as well. Really provides a good market base to push their product, which in turn funds their research.
Definitely a lot more to it all though, still need your panels, inverter (I know Google was pushing hard for a much smaller and more efficient inverter design **broken link removed** ) etc.
But either way, this is a great start and very exciting.
...This guy is pretty darn inspiring as well.