If I had pets, and could evacuate them myself (car, van, etc) they would come with me. If for any reason I needed to evacuate to a shelter, or on public busses, well, I don't think they would. The reason for this is simple...Shelter facilities are often strained to the maximum of their resources, as far as food, water, and sanitation are concerned. There are people in them of all ages and medical conditions, and I could not countenance being the cause of someone who has already gone through the trauma of being evacuated becoming ill through allergic reactions to pets, especially in an emergency like Hurricane Katrina, where medical help was thin. Also, for those who have large breed dogs, the idea of risking human lives by filling rescue bus space with animals is just wrong, no matter how much you love them.
People must come first.
That said...If I were evacuating under my own steam, and to a friend or family member's home, or a hotel where animals were allowed, of course, they would come with me.
Again, let me say that if it were possible, the animals would come with me, to a place they would be welcome. I don't see how I can allow the illness or exclusion from immediate evacuation to safety of a human being for the sake of an animal, no matter how much I loved that animal.