I am the first one to support the notion that every little step counts to save energy and reduce our footprint. The recent discussion about the primarily white background of the Google search homepage seems a bit far fetched though.
Check out "blackle", a google search site all in black....not sure it will take of.
Similar idea, but custom here:
I think if people turned off their monitors and unplugged their laptop power adapter at night, lots more could be saved.