Luckily, Gustav did much less damage than feared. But we learned that New Orleans- and by implication, any major city- can be evacuated in time.
The reason FEMA did a terrible job taking care of the victims of Katrina is that Bush made a terrible pick to head it. But the reason there were victims is that the Mayor didn't evacuate the city- let that horrible photograph of a huge parking lot full of unused busses soaking in floodwaters be a warning to all mayors of coastal cities, cities near faultlines, and cities near volcanos: Don't wait for the federal government to offer advice, don't hesitate for fear that if worst doesn't come to worst you'll catch heat for wasting money... if you get a warning, ACT. The only waste you can't explain away is the waste of human life.