I haven't seen this mentioned but if there is a run on batteries and flashlights, get some candles.
If you have a laptop computer make sure it is charged up - you'll have at least 2 hours battery life and can get to the internet thru dial up if the power is out but the phones still work.
And make sure you have a cheap regular phone, not a cordless. No need for power.
Yes, candles are necessary. Garden Ridge carries candles in very large glass containers that would last a very long time.