To add to all the awesome ideas, I would say never to underestimate the importance of hydration. Our bodies can endure quite bit, like going 3-4 weeks without food, but to get dehydrated in an emergency situation especially in any kind of remote area would be one of the biggest concerns in my book. Having a backpacking water filter and or a steri-pen or tablets would not only allow you to use virtually any water source for drinking, but it would considerably lighten your load so you can other important things as well.

Just my long drawn out 2 cents.