Cooking & Appliances
Camping cookware is useful not just for recreational camping trips, but also in an emergency. As camping cookware goes, solar cookers do a great job when the weather allows - and at an operation cost of $0. You'd be surprised how versatile solar cookers are. They'll cook and bake everything from rice to stew to muffins. However, they require full sunlight - and therefore extra planning - to use effectively.
For all-around versatility, you can't beat a good propane camp stove. They're portable, affordable, and they work in the rain, which can literally be a life-saver sometimes.