DaisyDisk is one of our go-to apps for investigating drive storage issues. It was a Readers' Choice Awards winner in 2010; a previous version was also a Tom's Software Pick.
The latest version of DaisyDisk quickly analyzes your drive and creates a sunburst map that displays how space is being used on your Mac. The map lets you navigate your drive to see which folders and files are using up precious storage space.
One of my favorite features is the ability to closely examine a drive's storage structure. Just click on the sunburst map and you can dive into the details of your drive's storage structure, and zoom in on data for a closer look-see.
There are many apps designed to help you figure out which files and folders are taking up the most space, but DaisyDisk always find its way to the top of my utility list because of its speed and ease of use.
If you have a drive that is bulging at the seams, DaisyDisk can help you make it slim and trim again.
DaisyDisk is $9.95. A demo is available.
See other software choices from Tom's Mac Software Picks.