Let's see:
calibre - For all my entertainment needs
Vim - for editing everything
Vimperator - for browsing
Mutt - To handle the huge volume of mail calibre users generate
kspace - For a mouse free desktop environment
python - to get my computers to do what I want them to do with minimal effort
newsbeuter - to read the few RSS feeds that aren't suitable for recipes
And then with my sysadmin hat on:
rsync, ssh, screen, apache2, sshfs, unison