How do I prepare my home for a power outage?
There's a few considerations based on the time of year -- when it's cold enough outside, saving the stuff in your fridge isn't as big a deal, as you can just put it outside (although, you might need to pack it in some critter-proof containers).

Good insulation can help in the colder months; Good tree planting and possibly some awnings on the windows or a good porch can help in the warmer months.

For general preparedness -- I like to keep at least one spare bottle of propane for my grill; one of these years, I'll get a heat proof thermal blanket, as I managed to cook a leather welding apron I tried using last year when cooking in a power outage.  (and don't think you can just go and swap out a tank ... when your car's been crushed under a fallen tree branch, and you've got no power for 2 days, it kinda sucks to run out of fuel.

Oh ... and pack your freezer and frige with water bottles.  It's thermal mass, and if you have to open a fridge, there's less air in the fridge that gets exchanged with the room temp air.  (again, not as bad a problem whem the house is 50 degrees, but it helps during huricane season).

If the power goes off in the winter, and you're going to abandon your house (go to a hotel, or a friend or relative), and it might be days before you come back to check on things,  before you leave, you may wish to drain the water in your pipes, so if the house does freeze you won't burst a pipe; then, when the house starts warming back up after the power comes back on, you don't come home to a huge mess.

Oh ... and trim the dead branches from trees, especially those above where you park your car.  (I'm not kidding about the crushed car thing when you're iced in with no power for 2 days ... it really sucks ... and looking out and seeing the office park across the street from you with their lights on)

update : 

A few more considerations -- look over what sort of systems fail when you loose power, and find suitable alternatives that don't require electricity, and would be useable in storm conditions.

For instances, people with sump pumps might want to consider a backup "water powered" sump pump

For heating, if you have a fireplace you rarely use, it'd be good to clean your chimney over the spring or summer and not in a panic when you're trying to prep for everything else; a chimney cap to keep out birds and leaves will significantly reduce the risk of a fire.

If you've got a generator, you might consider building a suitable location to run it from, away from your house, so you don't risk exhaust coming into the house and CO poisioning.

You might also want to test your emergency systems -- make sure generators start, make sure a squirril hasn't chewn through the gas line to your grill (yep, had that one happen, too), or set up a nest inside your grill (happened to a friend), etc.

Also, you may want to consider re-adjusting the circuits in your house;  yes, there are laws against 'suicide cables' to connect a generator to the grid, but if you shut off the mains from your house, you can connect up the generator, and then just turn on the circuits you need on; unfortunately, in my house, the pumps for my radiators are on a different phase than my oil burner; if I had the fridge and heating all on one phase, I could keep it all going with out needing a 220V generator.