If you're not a B & B person> We've stayed at the Omni Royal Orleans a number of times because you can't beat the location. You won't want to stay on or just off Bourbon St. and the Royal Orleans is 2 blocks from it and it's also right across the street from Emeril's NOLA, an excellent restaurant. Also next to Napoleon House, a bar/restaurant that's straight out of a Tennessee Williams novel.
I'd also recommend staying at a plantation. See: http://www.southernliving.com/travel/plantations.asp
We stayed at Nottoway: "Because it is thought to be the largest plantation house in the south, Nottoway is nicknamed The White Castle. As you pull into the long drive, the expanse dwarfs the river levee.

Built by Mr. and Mrs. John Hampton Randolph (their portrait overlooks the entry) in 1859, the house has 64 rooms, 200 windows, and 165 doors. They needed the space for their 11 children."