Sorry, I'm not sure what you call those applications, so I didn't know what to search. Anyway, I know there are stuff like that for Windows, you can see how much free space your hard drive has and you can also tell where the big files are. Sorry, that's a really poor description. But I would like to ask, are there any like those for OS X?
Whatsize looks very nice, but unfortunately it's not free... I'm downloading Disk Inventory X right now. Thanks!