A world atlas probably won't do you much good, but a local street map can certainly go a long way if you need to get out during a disaster situation. Google Maps, MapQuest and GPS all require electrical or battery power and an Internet connection. That's not to mention that sometimes they're plain wrong on the directions front.
A paper map is a good backup in case you're trying to get out of town on a road less-traveled. Make sure you have a street-level map and practice using it before you have to. Bonus: the map may have additional uses if you can't find the phone book [source: Jorgustin].