Paracord is a very strong nylon material that can be used whenever you need rope. It has so many uses: shoelaces, fishing line, securing a shelter, tying items to your roof rack, and much more. Paracord can even be used to repair things around the house. See Paracord to the Rescue
You can keep paracord handy for emergencies by wearing it as a bracelet or belt. Check out this review of Ridgerunner Belts by the Prepping Guys.