try Filelight
it' s the coolest approach to disk usage display: TRY it!
You can also try KDIRSTAT wich is more serious and with a lot of functions, but less informative. It use treemap display: lot of confunsing squre one inside other to display disk analysis.
or
BaobapOpen Sourcehttp://www.marzocca.net/linux/baobab/
.
Filelight Filelight is an open software that shows your filesystem as a set of concentric pie (sunburst diagram)Open Sourcehttp://www.methylblue.com/filelight/.
GD MapOpen Sourcehttp://gdmap.sourceforge.net/.
KDE FSViewOpen Sourcehttp://docs.kde.org/kde3/en/kdeaddons/konq-plugins/fsview/index.html.
KDirStatOpen Sourcehttp://kdirstat.sourceforge.net/.
xdiskusageOpen Sourcehttp://xdiskusage.sourceforge.net/check also http://www.dmoz.org/Computers/Software/Disk_Management/Usage_Analysis/
For windows a lot of disk usage tools are available (most as shareware):
Space Searcher
FolderSizes - Disk Space Management Software
