We bought a house with a solar installation, which has been keeping our electric bills low, but we never hit zero before. Last month I did an energy audit of our place, and we just got our first zero dollar energy bill.
That's mostly a symbolic milestone, since we were pretty close in the summer anyway, but I also figure we cut about 3.5 kWh/day, which is a decent chunk of our total grid usage for the last year. I think that some heating/AC adjustments should get us to net neutral.
These are great, by the way:
http://www.amazon.com/gp/product/B0035GAXA8/ref=oh_details_o00_s00_i04?ie=UTF8&psc=1I have one on a receiver that draws 22 watts when off, but I didn't want to have to plug/unplug it all the time. That little guy keeps it off when I'm asleep and at work, and should pay for itself in about a year. (I have another one power-cycling the DSL modem once a week at 4 AM, which did wonders for my internet connections' stability.)