There are two modes of LCDs, normally white and normally black. This means that, at rest, not powering the transistor, the window (sub-pixel of the LCD) is either open or closed. LCDs were once all “normally white” since a display is usually more white than black (look at your PC monitor). Normally white will use less power if more of the display is white or a light color. This mode was picked years ago so notebooks would use less power. The problem arose when the notebook industry, followed by the monitor industry, and finally the TV industry found that dead transistors meant that the little sub-pixel window is “open” all the time. This is the cause of the dreaded stuck bright red, green or blue dot.
The answer is that all large area LCDs are normally black. Normally blacks use more power on a typical image (if there is any such thing as a typical image), than normally white displays. So, today’s set use more power but the dead pixels are black and not stuck on. A fair compromise in my opinion.
DB

While it's true that a black pixels consumes less power than a white pixels on a CRT screen, pixel color has no effect on LCD power consumption. Given that LCDs are a large and growing (and possibly majority) portion of the global monitor population, the power savings claimed by blackle.com is a case of diminishing returns.