One of my 9 Rules to Creating a Logo is to design it in black & white only. The reason for this is that you don’t want the client to focus on the colors in the early stages of the design. It’s more important to get the typography and the actual logo mark right before worrying about specific colors.
That being said, once the client approves the basic logo, it’s important to choose the right colors. Color needs to be appropriate for your product or service, but it also needs to stand-out from competitors. When you look at the logos of large companies, you begin to see a reason for the colors they chose.
WeLogoDesigners has published A Guide to Choosing the Right Colors For Your Brand that offers some advice and psychology behind choosing the right colors for your logo.