The ability to just boil water goes a long ways. A lot of good stoves out there can't simmer well, but they are awesome at full power and can boil water. With boiling water I can make tea, coffee (a thermometer so you can use the water at 200°F also helps the brew), hot chocolate, Ramon, Lipton Cup-a-Soup, et al.

For the purpose of boiling water I have an old tea kettle and a Pocket Rocket with fuel canisters in my truck. That said, most any good stove will do.