(expired link) Thermal Depolymerization: Turns any hydrocarbon waste (from old tires to turkey guts) into oil, natural gas, water, CO2, and trace element sediments. An experimental plant is already running. This has the promise to totally eliminate the landfill problem, and help wean us off dependance on Middle Eastern oil. In addition, because the fuels produced were made from materials that were already at the surface -- and in many cases made from biological materials -- it's a closed loop; no new CO2 is added to the atmosphere by burning them.
Broad-Spectrum Solar Cells: If they can be mass-produced cheaply, they'll up the efficiency of solar power by at least a factor of five. This is a long way off -- at least 20 years, probably -- but still, if the tech goes commercial, it will suddenly be economical to build every new house with a bank of solar cells on top. The cells would generate enough power to pay off their installation cost within a few years, and enough to cover any maintainance costs, with plenty to spare.
And, most interestingly if you're into nuclear, it turns out that back a few months ago, while everyone was distracted watching news about yet another war in some country that has lots of oil, the folks at Sandia Labs got an experimental fusion generator operational. The concept is old, but now they've actually built the thing and fused some hydrogen in it. Yet another technology to keep an eye on. Between these three, we just might kick the fossil-fuel addiction within the next couple of decades.
Lastly, what prompted me to make a post now, is a new concept that may soon replace the rechargeable battery: Microengines. I highly recommend following the "Research TV" link, and checking out the video on the subject.