SC-DiskInfo is an easy to use disk space usage analyzer that allows you to see which folders take up the most space. It displays number of subdirectories, file count and overall size, as well as a graphical chart display to quickly spot the largest folders. You can sort the report for all columns.
At installation, you have the option to integrate SC-DiskInfo with Windows Explorer.
Caution: This software requires Windows 2000, Windows XP or Windows 2003 and does not work on Windows 95/98/Me/NT.