When I visited New Orleans (never again -- it was not a fun place), we were forced to pay an outrageous amount to park at the hotel. I think it was something like $30/night, and it wasn't safe; some of the cars in the guarded lot were broken into during the night.
If you're staying in the French Quarter, you probably don't need rides; everything's quite close.
The inner parts of New Orleans were not made for cars, so you will pay a lot to park there, or you will have to get creative and walk a long way. It's an economic disincentive to bringing a car into a real city where it has no place.
New Orleans is also not for everybody. If you love places that are clean, orderly, and quiet, you will probably hate New Orleans. If you always look for the parking space closest to the door, you will probably hate New Orleans. On the other hand, if you are looking for a place that's got some life to it, that is walkable, that has character, and you don't mind a little grime, then you should definitely go.
And if you decide to take your car into New Orleans, don't leave stuff visible through the window. Put everything you leave into the trunk. It's New Orleans, not Iowa.