This tool gives two views that rock: a tree view with each folder’s space taken next to its name, and a second graphical view that shows files in terms of size. The graphical view is even clickable, such that it will take you to the file in the other view so that you can identify it and see if you want to delete it. Folders get smartly color coded … seriously, try it out.
Its free from a sourceforge project, so there’s not a lot of downside. Unless you’re the kind of person that’s quick on the delete key. Then, its like pointing a loaded gun at your foot. Foot … meet delete key. Not good.
Anyways, try it out. I like it and use it on my windows partition of my MacBook Pro. With 40 GB, space is at a premium.