In addition to complaints about the federal response to the disaster, much of the city's own social services proved to be unequal to the task of handling the storm's effects.
Scenes and stories of looting, violence in the streets, deaths in hospitals and nursing homes and police brutality ? including the alleged murder of innocent civilians -- have become emblematic of the failures in the immediate response to Katrina.
Across the Gulf coast, more than 300,000 homes were reportedly destroyed by the raging floodwaters and other effects of the storm.
Still, the vibrant, iconic city known as the Big Easy is slowly making a recovery.
This week, a team of volunteers with the St. Bernard Project is coming together to rebuild the Dorsey's home in another part of town.
"It will be wonderful to sleep in our home, here in New Orleans, once again," Dorsey told ABC News.
The population of New Orleans has rebounded to nearly 80 percent of the pre-storm levels, and wages are up by 14 percent.
There's a new police chief, who is vowing big changes in an effort to repair the force's badly damaged reputation.
"I know we can reduce crime and I know we can increase people's quality of life," Ronald Serpas, the new chief, told ABC's correspondent Bob Woodruff.
Fifteen billion dollars have been spent to rebuild and improve the flood protection system that failed miserably in 2005.
Some residents have returned to areas that were inundated. Among them is Wanda Leigh, who rebuilt her home right beside a brand new flood wall.
"It's an unsettling feeling," she acknowledged, but added with a laugh: "Well, I have flood insurance now."
In Hancock County, Miss., not one home on the 7-mile beachfront remained intact. All told, the country sustained $130 billion in damage, and was allocated more than $500 million in aid.
That was the key to its economic renewal and recovery.
In five years, the Gulf has undergone a major transformation.
Like so many Gulf Coast families, Nora and Ed Wikoff decided to stay and rebuild.
"This is a great opportunity, I think, for our community to make some significant improvements. You can see some of that happening," Ed Wikoff told "Good Morning America."
Roberts visited the areas affected by the hurricane for a weeklong series titled "Road to Recovery."
Les Fillingame is the mayor of Bay St. Louis, a Hancock County city that was battered by Katrina.
He said that he's seen the benefits of the federal aid.
"It's an investment that will show returns in this area, and even in the national economy, for generations," he said.
Restaurant owner Jamie Temple is banking on it.
"We're very lucky, I was actually opening the weekend of Katrina and the building got destroyed, took 19 months to actually get it all together," said Temple, who runs The Buttercup, a restaurant on Second Street in Bay St. Louis. "And I'm so glad I did, and even though there was nothing left, it was the town that brought us back."