I think there are many scenarios that I would stay put, and a few that I actually would break for the hills. I have 3 boys (10, 3 and 1.5). The eldest could hang pretty well in a survival situation, but the others are too young to haul out of the house for any but the direst of situations.
The current plan is to find 100 acres to split with a good local friend. I would stock that location and feel comfortable taking the boys there. but until that time, I think we are most apt to hold up at home.