Tools to visualize file size distributions

I am using Disk Usage Analyser (aka Baobab), its output looks like this. (It's a png, couldn't paste it here). I believe it's part of the regular Ubuntu installation.

Also, there's KDirStat, of which WinDirStat is a clone. Here's a screenshot:

Check out this page 6 Great Apps to View Disk Usage in Linux for a collection of other tools.

I am using ncdu for that purpose on the command line. The Homepage of that tool includes a list of similar software: http://dev.yorhel.nl/ncdu

On KDE there is Filelight, which does a similar job, but with a slightly different representation.

Another ncurses alternative is ncdu.