Shortly after my wife and I got married there was a major ice storm which knocked out power to our home for a couple days. We had just purchased a side of beef which was chillin' in the freezer locker, and I was worried that we would lose the whole thing. Fortunately the meat stayed frozen until power was restored, but I swore my family would never have to go without power like that again. That season I purchased the largest portable generator I could find, a Generac 7000EXL just like this one...
Then a couple years later I had an electrician wire the essential circuits into a sub-panel which connects to an auxiliary cable. So now when the power goes out I roll the generator out of the garage (or if it is still storming I keep it just inside the garage and open the door to let out the exhaust), plug in the cable which runs directly up from our basement to the garage, flip a switch to prevent electrical back-feed, and start it up. I run the well pump, fan for the oil furnace, kitchen outlets, satellite TV, wireless DSL, and of course the refrigerators and freezers, all without running a single extension cord through the house. Here's a pic I found showing how it works...
We've survived for days running on this generator, to the point that the power company brought fuel to us to keep it running when they couldn't get up our road to repair our line for five days, and we couldn't get down to get gas. Over the past ten years or so we have used it countless times, from an hour or two to several days at a time. We are in a rural area so trees bring down the lines frequently, though to my surprise we didn't lose power at all when Irene passed by.
I will never, ever have a home without this feature built in.