When it comes to what is often called "fashion color" (basically hair colors not found in nature) I think there is a fine line between beautifully done, and manic-panic-in-the-bathroom style. In my opinion, keeping the color dimensional, whether you're going brunette or hot pink, keeps your coif looking super awesome and professional. And of course if you're wanting to do something fun, but don't want to deal with your whole head being colored, peek-a-boos in all colors of the rainbow are really fun and low maintenance.