If I had to leave and could only take 1 thing with me?
It would have to be my best companion who has traveled with me since 1997, my Lemond Zurich bicycle with Campy Record ergo power shifters and drivetrain, with Mavic Cosmic aero rims.
Never can tell when you're gonna need to go somewhere relatively fast (I cruise at 20-25 mph), and besides, I've got too many miles in the saddle on it to even consider leaving it behind. Not only that, but you can use a bicycle strapped to a set of rollers as a way to generate electricity.