When you get to own a color as much as Coca-Cola does, you don’t need much more around it.
The wrong color can make a great logo look like something a friend left on your bathroom floor the morning after a party.
Take a look at this brief article at FastCoDesign, then ask yourself: How much does color define a logo? Truth-be-told, you should probably spend nearly as much time thinking about your color use as you do designing the logo.