It seems that utility power interruptions are only getting more frequent and longer in duration with each passing year - to the point where having a standby generator is 'cheap insurance'. Along that line, it's amazing how much the prices for gasoline, propane, and even diesel generators have come down lately ...
http://www.generatorsales.com/used-generators.asp?gclid=CKLF8973up8CFdRM5QodL2yK3g Despite the fact that my 10+ year old Honda gasoline generator is still runnable, I'm seriously considering investing in one of these diesel generators for emergency backup. Operating fuel costs are significantly lower per kW per hour than gasoline or propane, and expected engine life is significantly longer as well. Also, home heating oil ( sans diesel road tax cost ) works perfectly well in small diesel engines. Thus for anybody with an installed fuel oil house furnace like I do, you've got 200+ gallons of generator fuel storage on site already ! And for the future, there's always the possibility of homemade bio-diesel !
But the same situation exists if your house has propane appliances with a decently sized tank the generator can be 'tapped' into. And there's no ick factor having to handle liquid fuel cans. But on the minus side, if you run your main house propane tank empty, you're going to be swinging wrenches to hook up barbecue grill tanks every few hours !