Here's a good link by the Government of Canada. It is meant to account for mundane disaster scenarios far outside of the scope of things I'm worried about, but nevertheless it includes some very good information about how to be prepared for a short term apocalypse:
http://getprepared.ca/Good for a handy first step in the apocalypse, where you may have to stay holed up for a short time while a majority of the populace moves on or dies.