Here is a few examples of different color schemes:
multicolor
red, orange, purple, green, blue
http://www.loc.gov/index.html
three color
yellow, blue, red
http://www.howstuffworks.com/
two color
red and blue
http://www.about.com/
two color
blue and green
http://www.space.com/
arguably monochrome
shades of red (with black…)
http://www.gutenberg.org/wiki/Main_Page
arguably monochrome
shades of red (with black…)
http://www.artsandlettersdaily.com/
monochrome
white on black
http://www.bwcitypaper.com/1homebody.lasso
