Here's a nifty little command I used today to find where my hard drive was being most used:
du -k /home/peterbe/Documents/ | sort -n | tail -10
I'm sure there are even fancier methods and programs but this works pretty damn well. Here's what the output can look like:
root@trillian:~ # du -k /home/peterbe/Documents/ | sort -n | tail -10
4240 /home/peterbe/Documents/Kalle
4852 /home/peterbe/Documents/ChartDirector/lib
7756 /home/peterbe/Documents/ChartDirector/doc/cdpydoc
7764 /home/peterbe/Documents/ChartDirector/doc
13044 /home/peterbe/Documents/*** FONT _ ***/- Font Applications -
14704 /home/peterbe/Documents/ChartDirector
547940 /home/peterbe/Documents/*** FONT _ ***
2171000 /home/peterbe/Documents/MacOSXSoftware/Adobe Creative Suite 2 Premium
3262580 /home/peterbe/Documents/MacOSXSoftware
5694808 /home/peterbe/Documents/