I guess Louisiana and Mississippi and Texas ought to be ready and willing to take this one from Florida, but it is not nice to think about. I have always worried about one coming up the Miss R and into New Orleans. I was there for Betsy and it was scary, scary.
A category 5 storm is very rare, and Ivan likely will be one, if he gets into the Gulf. New Orleans could not survive any Category 4 or 5 storm that directly hit from the southeast or southwest, and even a slow-moving Cat 3 storm would accomplish the same thing. But I think most residents have had that fact drummed into their heads by now, and hopefully they'll act accordingly.