Navyvet, I can't remember which thread, but didn't you say once that experts predict that the population of NOLA will be about 175,000 as opposed to the nearly 500,000 people who lived there prior to the storm?
This sounds like a reasonable estimate to me. Many of the people who evacuated are now putting down roots somewhere else. People who have found jobs and housing elsewhere may very well stay elsewhere.
People will settle where there are jobs, and there will always be jobs in New Orleans because of the port. Regardless of how the city is rebuilt, there will also be lucrative jobs for builders and engineers, at least throughout the rebuilding process. From what I've read on this board, it sounds like there are also jobs available for food service workers, although food service salaries aren't usually high enough to attract workers (below the managerial level) to relocate for those jobs.
Navyvet, I think you also said that much of the subsidized housing is being rebuilt, and that many welfare recipients are planning to return.
I think there will be a change in the demographics of New Orleans, but I think at least a portion of the city will remain and be populated.