Pertinent to this question I just asked [Find files taking up 80% of the space on a Linux Webserver](https://serverfault.com/questions/43296/how-does-one-find-which-files-are-taking-up-80-of-the-space-on-a-linux-webserver/43302#43302)

I think a programme like this would be excellent. Up to date info about files & folders on the system and what space they were taking.

You could even throw in some warning info about permissions.

Does something like this exist?

I keep thinking of the windows app Treesize which I used back in '98 days.