I don't know about a full-blown disaster like what is going on in the mid-west or like Katrina hitting in 2005, but I do try to keep some basic stuff around. I live in an area where one storm can knock out power for a minimum of a couple of hours. In 1998 we had an ice storm on December 23/24 that knocked out lines for days (10 in some parts of the area) and since then, the Coop has been good about keeping right of ways clear. Of course, when Isabelle came through in 2003 that didn't matter.
In any case, based on that, I've learned to keep old gallon milk jugs around filled with water for flushing the toilet (I'm on a well and when power goes, the pump doesn't run). I keep candles, matches, lighters and oil lamps for light along with flash lights. I make sure I have propane in the tank for the grill so I can cook.
If I ever had to evacuate, I have all my vital papers in a fireproof lock box that I can just grab and go. But I found out a few months back when we had a forest fire near my house that I need to organize the stuff I don't want to lose a bit better. When I was getting stuff together to leave for a night during the fire, I had way to much I didn't want to leave behind like photos. I can't imagine what I'd do if given only an hour to get out and a limit on what I could take.
Michelle