I'm happy to report that in the year that I've owned my generator, we have not lost power once. It's kinda like bringing your umbrella to work, almost guarantees it wont rain
Actually, we've been over this time and again.
For battery backup, your best bet although almost as expensive as a generator is a Power Inverter and a deep cycle battery.
The $12 PenPlex D battery air pumps work good also for smaller tanks.
Computer UPS's will work for short periods of time, but are by far the least cost effective (unless you happen to hace about 30 in your garage
If you can get home to start it, the gas generator is your best bet.