Most nights there are folks in the quarter (at least from Spring -> fall).
When you get to the quarter, get a hand grenade. There are two tropical isles on the main strip, one right on Bourbon, the other right off. They are said to be "New Orleans most powerful drink." But, you can't really taste the alcohol, and I tend to overdue it.
Pat O'Brians is a nice place to chill for awhile. The piano room is good, especially if you go real late, when you are really hammered. I've spent many nights in there with a couple groups each playing college fight songs of their hometown while singing at the top of their lungs. It's fun stuff. That usually seems to happen pretty late in the evening.
Next to Pat O's is Jazz Preservation Hall. Two performances a night, I think. It's only like $10 to get into a small room and watch some guys play genuine NO jazz. It sometimes gets hot in there.
The aquarium is cool. The IMAX shows a bunch of crappy movies, but they don't charge all that much for it. It's between Harrah's and the French quarter for the most part.
There is an art museum out towards Metaire that was pretty good. Haven't been to it in awhile.
If you are there on a Saturday, look into going to Abita for a brewery tour. It's about 40 minutes away (across the causeway bridge into Abita Springs). Free tour of their brewery (great beer; I was also their webmaster for a year or two) and then you can drink for an hour or two. My suggestion is catch the early tour since they just drop you off in the break room afterwards. Then, you could drink the whole time the next tour is walking around. Friendly folks here, too. There is a brewpub around the corner if you want some lunch.
Magnolia Mansion is where I stayed last time. Got a $89 rate from Travelocity. It's on St. Charles in the Garden District. Cab ride to Harrahs and the FQ was about $6, so not very far. The Real World house was about 5 blocks down St. Charles and was currently being gutted and re-done from the looks of things. It (the Magnolia Mansion, that is) was an old mansion with 12 or so rooms. Each was styled in a different theme (Vampire Room, Gone w/ Wind room, etc). The wife loved it and I got some points for that one.
I usually hit up Harrahs for a couple drinks. Go to the French Quarter and hangout for a few hours. Go to Pat O's and make an @ss of myself in the piano room having a great time. Hit up Cafe Du Monde (two blocks away) at 4:00am, then head back to the hotel for sleep and recovery time.