The size of debian packages

[Andrew Lyon <lyon@hep.man.ac.uk>]

Hello,

Since installing Debian in May the amount of disk space required for my OS
has risen from 1.5GB to 3GB and has reached the limit of the partition.  
I don't really want to allocate any more space to the OS as I'm sure there
must be stuff there that I do not need or use (I admit to running dselect
a little to liberally in the past!). How can I find out the sizes of the
packages and try to establish what I can remove without disaster. I tried 
using deborphan to do this but it didn't even put a dent in my 100% full 
volume.

Ideas appreciated.

Thanks
Andy