I'm not sure if the obsession with office supplies is a 'dietetics thing', but I adore colorful sticky notes, pens, and anything that will help organize my life. When I saw this design concept for a color cartridge pen you better believe I tried to find a real one.
Color coding within my home office is a technique I use in a quest to somehow generate a 36 hour day. Note: So far this has proved to be impossible, but I'm still trying. In a sea of black and white papers, a vibrant color helps grab your attention to something important. Use your favorite colors to make tasks more enjoyable (really, it's the little things) and splurge on the cute pink paperclips.
I try to limit my color coding system to 3-5 colors. Any more than that and the brain has trouble remembering quick cues of what corresponds to what. With a system of organization that only requires color matching, it makes for speedy and relatively painless desk clean up.
So what about the desktop? Look at your screen. Can you even see your background picture? A cluttered computer screen is just as bad as a junk piled table top and sure to fill you with anxiety. Make folders that color correspond to your paper system. If orange is insurance related on paper, the orange folder on the desktop is for the same. Also keep in mind you're completely within your rights to 'sub-folder', meaning add folders within folders.
The goal is to make things logical to find and make your life more efficient. No system works for every person, so do what makes sense to Y-O-U! How do you organize?