Disk Usage Explorer - A program to visually show the disk space distribution - http://siddharth.homeip.net/due/
O&O DiskStat - Displays disk usage as rendered 3D bar, doughnut, and treemap charts, optionally grouped by file type or owner. [Windows 2000, XP, 2003, Vista] - http://www.oo-software.com/home/en/products/oodiskstat/
Dirlot - free folder size visualization utility - Shows relative size of files and subfolders in a folder on disk using interactively explorable and colorful diagram report. [Windows 98/ME/2000/XP] - http://soft.km.ua/soft/dirlot/index.en.html
TreeSize Professional - Hardisk space manager for Windows 95/98/NT. Shows folder or drive size, wasted space, 3D bar and pie charts, last access date, searches for old, big files. Explorer-like interface, Excel or text export, context menu support. English or German shareware fr - http://www.jam-software.com/treesize/
SpaceObServer - Hard disk space manager for Windows. Scans directory trees and stores the collected data in an SQL database. A user interface reports space usage, growth and more in tabular views, 3D bar, pie and line chars. Integrated file search. - http://www.jam-soft.com/spaceobserver/
SpaceMonger - Displays files and folders as boxes, with sizes relative to space taken on disk. [Windows 9x/NT/2000/ME/XP] - http://www.sixty-five.cc/sm/
Filelight - Filelight is an open software that shows your filesystem as a set of concentric pie-charts. [Unix] - http://www.methylblue.com/filelight/
Drive x-Ray - Drive x-Ray is a visual tool for finding and freeing disk space. - http://www.tdp.cz/products/xray.shtml
MBS Disk Space Analyzer - Disk space analysis and cleaning software for Windows 98/ME/XP. - http://www.craveworldwide.com
WheresTheFreeSpace - A hard drive free space analysis tool for Mac OS X - http://www.wheresthefreespace.com
Disk Recon - File management tool that includes folder sizes, file search, duplicate file finder and file monitor. [Windows 98/ME/2000/XP] - http://www.blacksunsoftware.com/diskrecon.html
SpaceSearcher - Analyzes space usage on drives or network share drives. Detailed reports and 3D bar charts of hard drives can be viewed, printed, and exported to Excel or HTML. - http://www.coolutils.com/SpaceSearcher
OmniDiskSweeper - A utility for finding and deleting big, useless files to free up space on your hard disks. [Mac OS X] - http://www.omnigroup.com/applications/omnidisksweeper/
ShowSize - ShowSize lets you see folder sizes, unused files, and also lets you print folder contents. [Windows 98/Me/2000/XP] - http://www.showsize.com
Junkfind - Cross platform tool that helps graphically find and remove folders that take up excessive space. Uses rectangular boxes to represent folders based on their relative size. - http://junkfind.kniberg.com
FreeSpace - Monitors hard disk free space in real time. [Windows 9x/NT4/2000] - http://www.pro-jets.it/en/freespace/index.htm
DiskView - Integrates with Windows Explorer to present visual indication of disk usage. Provides a visualizer pane for pie/bar charts, adds folder size columns in the details view, and size indicator bars in Explorer's tree view. [Windows 2000/XP/2003] - http://www.diskview.com/diskview.htm
Disk Size Manager - Provides pie and bar charts of disk usage in a file manager interface. Includes a tool to conditionally search files and folders. [Windows 9x/2000/NT/ME/XP] - http://www.spadixbd.com/dsm/
Space - Disk usage analysis tool for Windows. Shows graphically how disk space is being used. Works on local and network drives, and FTP accounts. - http://www.andyhsoftware.co.uk/space/
Diruse - Command-line tool that displays directory size information, including compression information for NTFS volumes. [Windows 2000 with NTFS volumes] - http://www.microsoft.com/windows2000/techinfo/reskit/tools/existing/diruse-o.asp
FolderSizes - Shareware that creates visual representations of hard drive space utilization and folder sizes through multi-threaded analysis engine. [Windows 95/98/ME/NT 4.0/2000/XP and Internet Explorer] - http://www.foldersizes.com/
TreePie - Program to graphically display information about distribution of size in a tree directory. - http://treepie.sourceforge.net/
Disk Triage - Disk space sizing and analysis utility. Features visual graphs of the sizing data, with the ability to run in batch mode. - http://www.timeacct.com/disktriage/
Power Admin WatchDisk - Tool with command line support for keeping track of disk usage on a network. Provides graphical reports of disk usage, automated alerts and data export options. - http://www.poweradmin.com/watchdisk/watchdisk.asp
BAC WhatsGone - Does a scan of the selected disc or folder and then gives a color coded view of the disc space used by each folder. Includes CSV export option. [Windows 9x/2000/ME/XP] - http://www.bacsoftware.co.uk/whatsgone/home.htm
BytesBak - Maintains a history of disk space usage, allowing easier identification of disk contents that have been updated, grown or shrunk in size. - http://www.bytesbak.com
Rakersoft SpaceTrack - Disk utility that tracks, monitors and records disk space usage on a continual basis. Product specifications, screenshots, and downloads. [Windows] - http://www.rakersoft.com/
jDiskReport - Cross platform graphical disk report utility to analyze hard disks and collect statistics that can be viewed using charts and tables. [Free: Windows/Solaris/Linux] - http://www.jgoodies.com/
Ascendis DiskVision - Displays disk space utilization with detailed information. Supports easy management on individual files and folders. [Windows 95/98/NT4/2000] - http://www.ascendis.com/diskvision/diskvision.html
Directory Sizer - FranzO Software - Historical analysis of disk usage by directory. Charting and drill down with web UI. Designed for the enterprise with NT Services and remote install. - http://www.franzo.co.nz/dirsizer2/
Diskdata - Explorer-like application that displays disk space utilization in report or chart format. [Windows 9x/NT/2000/ME/XP] - http://www.digallery.com/diskdata/
3D FileSystem Profiler - Provides 3D visual representation of file system statistics. Aids in visual analysis of the disk space usage. [Java based] - http://visualversion.com/profiler/index.html
DiskSpaceChart - A small shareware utility that shows a 3D pie chart indicating disk space usage. [Windows 9x/ME/NT/2000] - http://www.silurian.com/win32/chart.htm
SizeWatch - Dynamically keeps an eye on the sizes of selected subdirectories. [Windows 9x/NT] - http://www.ahc.dk/eng/share.htm
SizeExplorer - Explorer style software that shows the actual space used by a folder. Shows graphical charts of file statistics [Windows 9x/ME/NT/2000] - http://www.sizeexplorer.com