They will be rebuilt. Part of that is because the administration is on the ropes on this one. But not all will come back. The jobs won't be there.
Well, to be clear, I am sure the neighborhoods will get rebuilt, and in the vague outlines that they will be patterned after the previous layout, but what I'm saying is that they won't get rebuilt in the "unwanted" state that they were before Katrina. If slums are rebuilt, they will be the nicest gosh-darn slums in the world. =)
It isn't jobs that most of those people want. They'll go where the government freebies are the easiest to get.