Echoing the others who would like to see improvements to configuring multiple displays. I'm really encouraged by Bryce Harrington's recent updates about an xrandr tool, very cool! re:

http://bryceharrington.org/drupal/display-config-0

What I think would take this to 'eleven' would be if the configuration could be saved in a way that you could have profiles for multiple scenarios. So that when you plug into external lcd123 that you configured in the past, that config is automatically found and applied. Then if you unplug and plug into a projector that you had used before then -that- profile is found and applied. So in essence you aren't constantly reconfiguring the same devices over and over. I switch between a number of different external screens with my laptop and it would be super sweet if things 'just worked' once I've gone through the initial configuration.

I think I would pee myself, actually.