DaisyDisk

DaisyDisk is a utility that helps you identify and delete large files from your Mac. It might prove to be of good use if you need to quickly reclaim disk space on your drive.
The program features a nicely-designed and intuitive interface, supports drag-and-drop actions, and works with various storage devices.

All you need to do is to select the partition, local directory or USB drive you wish to analyze and the application will immediately start the scanning process.

DaisyDisk then gives you access to a quality pie chart representation of the selected drive or folder. On the right side of the main window you will see a list containing the names of the largest files, nicely organized based on file size. You can drag-and-drop the files you wish to permanently delete to the bottom side of the interface and confirm deletion when prompted.

Personally, I'd prefer using Mac's Finder app instead of working this program. Finder provides you with various sorting features which help you immediately locate the files that take up the most of your disk space.