Almost all of the food we grow we put up if we can’t eat it fresh. We buy staples in 50lb bags and I have a giant stockpile of wheat that I inherited. We only grow open pollinated varieties and save seed for the following year. We have emergency water rations and first aid kits. We’re planning on getting a generator and looking into either a small windmill or some solar (though most solar companies laugh at us because we already use so little power).
We don’t do this because we think the world as we know it is going to end. It might end, who knows (hint: no one knows) but it isn’t why we keep food and water on hand. Peak oil, in my opinion, has already happened without so much as a squeak. As humans, we’re pretty good at adapting so we’ll figure it out. We can survive without cheap oil anyways, after all, we lived without it for thousands of years. Nuclear holocaust or super volcano? Honestly, I don’t know if I would want to survive either of those. A plague? You really don’t have any control over whether you survive or not even if you take all the necessary precautions. There are hundreds of scenarios of what could happen, but why worry about it when the chances of any of these happening is pretty small.
There are bigger things to worry about that you should be prepared for. Job loss in this economy is a real worry and much more likely than a nuclear holocaust. Natural disasters like an earthquake here, or a hurricane in the southeast are also real concerns. Blizzards, tornadoes, volcanoes, flooding, these are all real, common disasters that could happen any time. And for those, everyone should be prepared.