We were there for this last Christmas and had a great time.
First the knife content. There is an antique store specializing in swords and firearms on the north side of Dauphine St, or one parallel to it, somewhere between St Ann and Esplanade. I only passed by it in the evenings and never got to go in. The D-Day/World War 2 Museum was really good. We spent about 6 hours in there and only covered about 2/3 of it. Many of the displays gave you the individual soldier's perspective, from both sides of the conflict. I took a look in the yellow pages while I was there and don't recall seeing any dedicated knife shops.
Otherwise, the food was great all over, even at the little take out places. It seems that the local culture values the enjoyment of food more than in other places. There are the "must do's" like having beignettes and coffee and mufflettas (get half unless you have a very big appetite). If you like going out to fancier restaurants and will be there for a while, it might be worth it for you to buy one of those Entertinment coupon books for about $20 to $25. They can be purchased online. There are car rental coupons (I think Enterprise had the best deals, consistently) in the back that make the book worthwhile with just one use.
If you like Jazz, make sure you go to Preservation Hall some evening. At $8 per person, it was a fantastic entertainment value. We may go back just for that. Just don't go expecting some really posh setting. It is the exact opposite. There are no refreshments available (nor washrooms, I think) and you may end up sitting on the floor, in front of the band, like we did. We happened upon a designated "national park", on the south side of Decatur or Peters, between St Ann and Esplanade, that focusses on Jazz. They hold performances there but not at the time we were there. Of course, there are other jazz-clubs but most have some sort of cover charge etc.
If you have children, the zoo was very good. It is well organized and they have planted a lot of trees for shade and there is a large play area that our little monkeys really enjoyed.
A lot of the attractions are located in The French Quarter. Just outside The Quarter, accomodations are less expensive and parking is much easier to find. Be prepared to do a lot of walking since The Quarter is a pretty big area. The public transit system seems pretty good with many bus and streetcar lines along the borders of The Quarter. We missed taking the streetcar named "Desire".
We did not end up having time to go on a plantation tour. We have heard both positive and negative about these. There is a steam-powered (?)paddlewheeler that takes people for rides on the river. I think that you get on at the Toulouse Street Wharf behind the old Jax Brewery building.
Go to your local library or used book store and pick up a guide book and read up on the various attractions.
New Orleans is crowded but not as much as places like New York. The atmosphere is vibrant with lots of things to see and do. We found the people to be very friendly. It was a fun trip for us and would like to go back.
Enjoy!
Phil