It turns out that when you're down to your last moldy hunk of bread and giardia-laced mud puddle, letting it all melt away in a cloud of smoke for a few precious moments can mean the difference between giving up and giving the rat (eating) race another go. If history has anything to say, it's more common than you think for people to happily give up MREs and gunlord harems in return for hastening their ends with carcinogens wrapped up in tidy paper packages. In traumatic situations like war, cancer sticks are often valued more highly than food. Even in the current (more or less) pre-apocalyptic global economy, cigarettes are one of the stable forms of currency.
In arctic or alpine areas, survival kits may have additional cold weather clothing (winter hats and gloves), sleeping bags, chemical "hand warmer" packets, sun glasses/snow goggles, snowshoes, a collapsible shovel, a snare wire for small animals, a frying pan, a camp stove, camp stove fuel, a space blanket, matches, a whistle, a compass, tinder, medical equipment, a flint strike, a wire saw, extra socks and a tent designed for arctic use.
To me, the best option is to store emergency food. How much? If you have none, store enough for a few days. If you have enough for a few days, get enough for a week. How much you store depends on what time frame you think you're at risk for having to be completely independent. The early settlers of the southwest liked to store enough food for a whole year and still do to this day!