If you're near Jackson Square (and most tourists are at some point), the 1850 House is worth a look. It doesn't take long to see, and it's only $3. It consists of an apartment in the Pontalba Buildings that has been restored to look as it would have in 1850 when it was the home of a wealthy merchant. I was amazed at how large the rooms are. The bonus is the excellent shop (where you buy your ticket). It has a fantastic selection of books on NOLA topics.