Rendezvous has turned into a tourist trap. Its a great experience, it is unique, but everybody knows about it. The food, at this point, is not as good as it once was. Thats not to say it is bad, but its not the best Memphis has to offer.
Central BBQ is highly regarded by a lot of people. I believe its the #1 BBQ joint on one of Urbanspoon/Trip Advisor. I liked it, but I have had better.
The original Corkys is available. Let me say that this is much better than the Corkys chains that are out there, but most people have had Corkys at one point or another, so you may not want it.
Interstate BBQ is unique in that they offer BBQ spaghetti. I liked their rib meat, but I wasnt a huge fan of their sauce.
The Germantown Commissary has great pulled pork, but it is also very small. You need to eat there at an odd time of the day to get a seat.
Memphis BBQ Co, to me, is the best place to take a large group. They have an extensive menu, so you will be able to please people easily and they have a high quality BBQ offering.
The BBQ Shop is my co-favorite for Memphis. They have my favoirte sauce and an incredible set of ribs. I believe that USA Today voted them top 10 at one time.
My other favorite is the Cozy Corner. Dont go there at night, as you will see bars on windows all around you. It is right next to St. Jude and they have a great, great set of ribs. I wasnt as impressed with their BBQ sandwich, but they also had great Banana Pudding.
Topps is overrated.