GrandPerspective is a small utility for Mac OS X that can draw two-dimensional views of disk usage within a file system. This can help you to manage your disk, as you can easily spot which files and folders take up the most space.
Version 0.9.13 of GrandPerspective has just been released. It features the ability to store scan results to a file (in XML format), which you can load again at a later time. Furthermore, progress reporting for long-running tasks has been improved. The new release also includes various minor improvements and a few bug fixes.
The new release is available at http://sourceforge.net/project/showfiles.php?group_id=148156. More information about GrandPerspective can be found at the project's homepage: http://grandperspectiv.sourceforge.net/.