If you're in the market for a new TV, bear in mind that all plasmas and some LCDs will not pass energy star compliances, apparently.
That little finding is no news to me, as plasma TVs have always struck me as a pretty inefficient way to light one's home. (I mean, as in the amount of energy they consume for each candela of output, so that if you put the picture on a white screen, you'd use a light meter a standard distance away versus a power meter measuring consumption. Not that you'd use it for lighting, but this is the fairest test I can think of.)
The other day I was taking someone through the plasma/LCD jungle that electronics showrooms have become, and I hit on the best way to explain how to select the TV that's best:
I urged them to select the picture quality they'd be prepared to accept, then walk among those TVs and test the temperature of the screen with the back of their hand. Coolest display wins.
And that's as simple as it gets. Whether plasma or LCD, the amount of heat given off by the screen is a measure of the energy that this particular TV wastes. Heat is wasted energy, and also it prematurely ages the electronics and the actual screen elements, be they plasma dots or LCD domains. NOTE this does NOT apply to rear projection TVs or TV projectors, although the heat test is a reasonable guide to projector efficiency.
So that's the simplest thing you can do right now when buying, to ensure that the TV you buy os the most energy efficient. And you don't even need a Government dude with a pocketful of energy star labels to show you how it's done...