With DaisyDisk you can free up disk space by quickly finding and deleting big, useless files.
The program scans a disk and displays its content as a sector diagram where the biggest files and folders at once become obvious. To drill down to a folder, just click on a segment. To bubble up, click in the center. Move the mouse over the diagram and see the name and path of each file, and enclosed files (if any). Hit Space to quickly preview file content, without launching another application. Ctrl-click to open a file in Finder. NEW: Scanning has been optimized, now DaisyDisk is one of the fastest scanners in the market!“
(Via MacUpdate.)