I've lived in several different parts of the country (including a few months in NOLA) and I have never, ever, met people who love their city as much as New Orleanians do. I believe it is the most interesting and unique city in the US. I have done a lot of traveling around the world and when people ask me where they should go when they visit the US, my first answer always is New Orleans. the way it has come back (and still is coming back) since the devastation of Katrina is evidence of the resilience of the people who live there. I don't think of it as a "dirty" city, I think of it as a real city. the city where I live now has, honestly, few to no "bad" or rough parts. it's a major American city, but I swear we live in a bubble here. it is a beautiful bubble, and it would be really easy to stay here because life is pretty easy, but I am excited to get to NOLA and become part of the community there. the thing that most impressed me about Tulane is that it seems that everyone at the med school, from the top on down, is invested in and involved in the community and is working very hard to make things better for the people of NOLA (ex., the community health clinics that have opened to take the place of Charity Hospital).
and the food is amazing! it's not like everyone is eating po' boys and bbq shrimp every night. but when you do want to go out, there are amazing places to go. you can be as healthy as you want to be, wherever you are.
sure, NOLA is not for everyone, and if you have big reservations about it, then maybe go somewhere else and leave your spot to someone who can appreciate the city for what it is. or, go with an open mind...you might be surprised at how much you grow to like it there.