Kill, main, terrorize usa citizens with a good chance to live to do it angain another day.
Why don't they put police/national guard MP's on some commandeered air boats?
New Orleans is mostly empty right now. Over 80% of the people got out. Many of the people who are left might be able to give a terrorist cell a run for their money in a firefight. National Guard are coming into town. There are few easy ways to actually get out of the city at this point. There is no media to show your attacks on Americans, so they can't get the publicity that terrorists crave so much. Any victims of your terrorism come from America's underclass, to a large extent, so people really won't care all that much about their deaths.
All in all, not a great terrorist target.