Bread clips as power cord labels. Doesn't get much simpler or clever...er. Unplggd also suggests using them to label your cords at both ends so you don't have to do the 'tug test'. You know, when you tug on the cord to see which one reacts at the other end? For more tips about 'getting our home office wired for success' click here.
POST UPDATE: Need bread clips?? Click here to see how to make your own!