TestDisk

Hard disk failure recovery tool; tries to repair partition tables, boot sectors, MBR; allows to read and copy files from lost partitions; an undelete feature is also included.

Homepage: http://www.cgsecurity.org/wiki/TestDisk
Developer: Christophe Grenier
Version: 6.11 (April 19, 2009)
License: open source free software
Platform: Linux/Windows/Mac

JDiskReport

There are for sure a lot of disk space analysis tools, but I liked this German Java application a lot: JDiskReport. It is relatively fast and displays a lot of additional information. The space usage or number of files information can be grouped by location on the file system, but also by file size, modification time or file extension. All information can be displayed as pie chart, histogram or detailed list.

Name: JDiskReport

Developer: Karsten Lentzsch (JGoodies, www.jgoodies.com)

Homepage: http://www.jgoodies.com/freeware/jdiskreport/index.html

Current version: 1.3.1 (July 30, 2008)

License: freeware, partially closed source; open source release planned [see here]

Platform: cross-platform