My backup server and utility server is a ubuntu box in my basement. Nothing special, an old laptop with a USB drive attached for backups. Every night my machines rsync with it and keep files nice and safe.
Recently I noticed the main partition was getting a bit full. I have not had a linux box really run out of space in the past. I think my problem is that this was my first ubuntu install (I have done many since) and I think I installed too many default applications. I have been selectively removing programs to free space.
In the course of cleaning up here is a great post to help clean up some unwanted items.