Lots of people who visit New Orleans today are surprised to find the city in such good shape. The rebuilding effort has been long, arduous, and largely successful in most areas (with a few notable exceptions, like the Lower 9th Ward).
New Orleans would not be where it is today without the students, church groups, retirees, professional organizations and lone good souls who gave their time and energy to rebuilding. At least a million people, by one count, and likely many millions. Newcomers poured into the city after the storm, and many became new New Orleanians.