WinDirStat is a disk usage statistics viewer and cleanup tool for Windows based systems.

Scanner is a tool uses a sunburst chart to display the usage of your hard disk or other media.

SequoiaView is a disk browsing tool based on the principle of treemaps.

FolderSizes is a disk space management tool.

SpaceSniffer is a freeWare and portable tool application that lets you understand how folders and files are structured on disks.

SpaceMonger is a tool for keeping track of the free space on your computer.

RAWGraphs allows you to export visualizations as vector (SVG) or raster (PNG) images and embed them into your web page.