Mac: If you have a hard disk plagued with unnecessary, large files, you can clear them out fast with Disk Diag. The app quickly targets common culprits so you can get that extra disk space you need.
While not a comprehensive tool, Disk Diag will weed out unnecessary files very quickly. You open the app, point it at your home folder, and it will perform a quick scan. In a few moments, it will suggest a bunch of stuff to wipe and let you know how much space you can save if you remove it all. You can probably lose a few gigabytes from caches and other junk, but Disk Diag will also seek out large files on your machine. If you knock those out, you'll save even more.
I have about 24GB it would like to remove. While I'm happy with my current situation, if I run low on space, I know it will be able to tell me what's eating away at my drive pretty quickly. Not a bad free utility to have around.
Disk Diag (free) [Mac App Store]