I have just spotted an application available for your Mac which displays your file structure in a diagrammatic way, and let’s you navigate through the different hierarchies. I’m not sure how useful this is on a day to day basis, although it does integrate with the finder, offering QuickLook. It’s certainly some nice information design, worth downloading to experience the interactive navigation. You can check out the application here, it costs $19.95 if you feel so inclined but you can try it out for two weeks for free.