I've been using the AlertMe Energy gizmo for over a month now, and predictably I've become much more interested in my electricity consumption. Apart from the Google Power Meter glaring at me every time I visit iGoogle, it also emails a weekly summary of statistics.
I've started to consciously think about turning things off, just to try and get my history chart on a downward trend. And this is the premise on which the gizmo - and others like it - work. But without figures for gas usage it's still only half a solution. I suppose we'll just have to wait until 2020 when we all get our government-sanctioned smart energy meters.