The most energy efficient way to watch television is to not watch it at all, but if you must, Toshiba's Regza LCD might be worth a look.
The 42 inch Regza just won PC Magazine's first Greentech HDTV Award due to its low power consumption and energy efficiency. Toshiba's TV was also given high marks because the company itself is actively working to reduce energy consumption and minimize waste.
PC Magazine judged the TVs based on energy efficiency, recyclability, Energy Star certification, and overall green rating (design, number and type of inputs, intangibles).
Toshiba is part of the recently launched Electronic Manufacturers Recycling Management Company (MRM), which is developing a national take-back program open to all manufacturers.