GrandPerspective

GrandPerspective is a small utility application for Mac that graphically shows the disk usage within a file system. It can help you to manage your disk, as you can easily spot which files and folders take up the most space.

Free Open Source Mac OS X

Scanner

This tool uses a sunburst chart to display the usage of your hard disk or other media. The chart shows all major files and folders from all directory levels at once.

Free Windows

SequoiaView

Create a visual representation of the amount of space each file is taking on your hard drive. It creates a "squarified treemap" that makes it easy to see where all your space is going.

Free Windows