Blackle!

For those worried with energy consumption and all its downsides:

When your screen is white, may it be an empty word page, or the Google page, your computer consumes 74 watts, and when it is black it consumes only 59 watts.

Mark Ontkush wrote an article about the energy saving attributes that would be achieved if Google had a black screen, taking into account the huge number of page views. And according to his calculations, 750 mega watts/hour per year would be saved.

In a response to this article Google created a black version of its search engine, called Blackle, with the exact same functions as the white version, but with lower energy consumption, check it out.
http://www.blackle.com