If you haven't had a roast beef Poor Boy at Parkway Bakery and Tavern, put that on your list. Just make sure to grab extra napkins and pack an extra shirt to change into after you eat.
If you want to venture toward the Uptown area, Jacques-Imos or Clancy's are always solid. A little more pricey than a poor boy joint, but well worth it. Again, more "New Orleans Fare" than Cajun, but really good.
I'm sure the Buz'd signal has probably been activated and he'll be chiming in soon with more suggestions...