It’s sometimes difficult to find out what’s taking up all your computer hard drive space. That’s why I like these free programs which visually display the contents of your hard drive by file size. These programs make it easy to find and delete large files and directories that you no longer need.
For Windows – Disk Space Fan
Disk Space Fan shows you a beautiful fan of your hard drive space. Here’s a video of how it works. When you install the free version, it allows you to use the Pro version for free for 15 days, then it reverts to the free version automatically. All the basic tools are included in the free version though.
UPDATE: Daniel in the comments alerted me to the fact that Disk Space Fan is a ripoff of the Mac app DaisyDisk available at http://daisydiskapp.com.
For Mac – GrandPerspective
GrandPerspective for Mac OS X is similar to Disk Space Fan but chooses the box metaphor to visually display your files. The first segment of this video explains how it works.
For more ideas on saving hard disk space, look at the Lifehacker article How to Analyze, Clean Out, and Free Space on Your Hard Drive.