GrandPerspective is a small utility for Mac OS X that can draw two-dimensional views of disk use 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 1.5.1 of GrandPerspective has just been released. It features two minor improvements both requested by users. Firstly, the ability to report file sizes with decimal-based units (where 1 kB is 1000 bytes instead of 1024 bytes). Secondly, the ability to copy the path of a selected item to the paste board. Also included is a minor bug fix.
More information about GrandPerspective can be found at the project's homepage .