For a person who work a lot with the terminal-based system, screen can be quite handy application for me to work with. With one terminal emulator and run screen on it, I can edit a code, run irc, connect to ssh, reading a log and etc. I can detach and reattach the screen. If i accidentally close the terminal emulator, all I need to do is open it back and resume my previously-closed screen with the same state.
To start getting to know screen (for those who never installed it yet), run this command:
sudo apt-get install screenand
man screen
Other reference you might want to look at:
http://www.kuro5hin.org/story/2004/3/9/16838/14935
http://jmcpherson.org/screen.html
http://aperiodic.net/screen/