This is just a small hint, but it had bothered me for a while, so I thought I would share...
I use an external monitor conected to my Powerbook at work, but not at home. I found that if I hadn't logged out/in before going from one place to the next, it did not automatically see my other display. When I "detected displays," it found the display, but did not remember my settings for the second display. This got annoying to do every day.
I found the easiest way to fix this was to kill and restart the Finder. When it restarts, it recognizes the attached monitor and reverts to my stored settings.
Mac OS X Hints
http://hints.macworld.com/article.php?story=2002031910483915