Rice. This is an old standby. It can form the base of many tasty and nutritious meals. Be aware that although it requires no processing, it does require quite a bit of water to cook. It is most economical to buy rice in 40 lb bags and repackage it into buckets yourself, a 5 gallon bucket will hold a 40lb bag. For a bit more you can find rice sold pre-sealed in buckets from a number of sources.
A service interruption or a fuel crisis that takes your cooktop out of service for a week or two is the other hardship perhaps worth worrying about. It's not just about eating well: in an emergency, the ability to boil water is one of the best methods of making it safe to drink. While the owners of rural homes with 500 gallon propane tanks may have little to worry about, the rest of us would not be having fun. For those who cook using municipal natural gas, a simple backup is a small, countertop electric burner, costing about $15. Conversely, for people with electric ranges, a portable camping stove ($13) and a handful of dirt-cheap 1 lb propane tanks ($4 at any hardware store) can be a safe, no-hassle choice. A pound of propane can boil around 12 gallons of water; the entire setup is also very easy to put in a backpack if you ever need to leave - so it's basically worth getting either way.