I like a clean desk. A clean desk means less time spent looking for tools. Less time spent looking for tools means more time learning. Regie Routman has taught me to teach with a sense of urgency. Clean desks help me do that. One of the things that helps my kids keep their desks organized is their toolbox. I found them at an office supply store several years ago for 50 cents a piece.
They keep their whiteboard marker and eraser in their toolbox. (Nothing else is welcome.)
Whenever their whiteboard comes out, so does their toolbox. It's pretty handy, organized, easy, and helps us use our time for better things than rummaging for stuff that's wandering around the insides of desks.