No, your friend is full of it.
Honestly, I have always found New Orleans to be one of the least racist towns in America. Why? Because here we don't pretend that we are all the same. We don't pretend that we all grew up in the same place. We acknowledge our cultural differences, and in many cases celebrate them (Zulu Social Aid and Pleasure Club, anyone?).
We're all working together down here to make things better. What you're hearing on the news is doomsday journalism - you don't get to see the good stuff that's happening. I currently work rebuilding flooded homes, and I can't tell you how many times random strangers have pitched in to help. People on the street say hi to you and ask how you are doing - and are actually interested in your response. There is such a feeling of solidarity down here it's unreal. Everybody who is here is here because they truly want to be; it's very rare to find a naysayer at all.
As for Nagin, I don't think he's that bad. He did all he could during Katrina, and I don't think many other mayors would have fared as well. We didn't re-elect him due to race - the challenger was a career politician with tons of family connections and a slick image. He didn't seem real, which put many people off. Were there things that Nagin could have done better? Sure. Could he have evacuated every citizen? No way. There were TONS of buses going out of town before the storm, all of them full. Just because the news reported on a few buses that flooded doesn't mean that none were used. (Just you try to find about 1,000 bus drivers on short notice.)
New Orleans is a great place. It's both worse and better than the news makes it out to be. People are struggling to get some help from the government 2 years later not because they are black or white, it is because the government is huge and inefficient. They are hurting enough without the condemnation of the rest of the country. If you really want to help, come down here and pick up a shovel.