Ann Arbor, Michigan will be the first city in the United States, and to my knowledge, in the world, to only use 100% LED lights for their street lighting. In addition to saving US$100.000 per year in electricity costs, it is estimated that CO2 emissions will be reduced by the equivalent of taking 400 cars out of traffic. Lighting stands for more than 20% of all the power consumed in the United States.
LED lighting has been discussed earlier on this blog, here and here. LED lamps offer several advantages over traditional bulbs, as well as CFL low energy bulbs.