A note to all my friends and anyone else who reads this blog: the recent earthquake on the US east coast shows that the unexpected event will eventually occur. Prepare now while it's cheap to do so, both in time and money.
Have at least three days of food and water on hand for each person and pet in the house, more as you have storage for it. (You need at least a gallon of water per day per person.) Hell, throw in some comfort food stores too (liquor, candy, etc). The food should be suitable for long-term storage: canned meat, canned cheese and butter, rice, beans, freeze-dried foods, MREs, and the like. Remember that some foods need water for cooking, so factor that into your water stores.
Expect the power to be out. Flashlights, headlamps, candles, a camp stove, and some propane bottles will go a long way in the cold and dark.
A battery-powered radio or TV will help you keep connected to the world.
Keep an extra supply of your medicines on hand. The pharmacies may not be able to dispense or even order your meds when the power is out.
Keep some cash hidden away, so you can buy things in case the credit card networks are out with the power.
If you're inclined to firearms, have at least a pistol and a hundred rounds of ammunition. I carry a .40 Glock, but if I had it to do over again I'd go with a 9mm Glock. If you can, have a rifle and/or shotgun as well along with sufficient ammunition.
If you really want to get into the spirit of things, think of it as a game of preparing for the Zombie Apocalypse; it's amazing how well those scenarios translate into real-world disaster preparedness.
*Some* disaster is headed your way, whether its power outage from a storm, or an earthquake knocking out critical facilities. It will come as a surprise. You won't have enough lead time to get ready for it. Nobody will be there to help you in the first hours and days of the disaster. Look out for yourself first, so you can then look out for others.
PS. Here's a good roundup of links to help you get started: http://pajamasmedia.com/instapundit/008339.