Pioneer Plasma
CNET took 54 HDTVs and analyzed their power requirements to answer this question. The results are interesting, but not very surprising and include an estimated yearly expense for each. The yearly number is based on leaving your TV on for eight hours a day and sixteen hours in stand-by. While most technologies used similar amounts of power, there were some exceptions like the 65-inch Sharp LCD which uses almost 600 watts of power in their tests. This is more than any of the Plasmas which were around 500 watts for a similar size. In the end the size made the biggest difference and microdisplays overall used the least amount of power. As interesting as we find this, in the grand scheme of things it isn't a lot of money, even the most expensive TV only costs $19 a month to run.

[Via TVSnob.com]