This provides both a graphical and numeric display of used disk space.
Files are kept apart from directories in separate items to prevent cluttering of the display. Different colors in the directory tree visually separate the levels. Plus, the time of the most recent changes within an entire directory tree are display so you can easily see what object was changed last and when.
This stays on one file system by default and reads mounted file systems on request. It can scan FTP or Samba directories, or any other protocols KDE supports.
Predefined cleanup actions let you delete a file or a directory tree, move it to the KDE trash bin, compress it to an archive, or simply open a shell or a Konqueror window. You can also add your own cleanup commands or edit the existing ones.
There's even a report facility that will send an e-mail message requesting the owner of a large directory tree to please clean up unused files.