I <3 BBQ, so I'll add my 2 pennies:

Texas Pit in Saginaw, TX. Right down the street from my house. The meat is fantastic, but the potato salad sucks. Their fries are made from scratch and incredible, though.

Mike Anderson's, in Dallas off Harry Hines.

Golden Rule, Birmingham, AL. Best pulled pork I've ever had.

Elmer's in Tulsa, OK, which unfortunately closed a couple years ago. They had a "sandwich" they called the Bad-Wich, which was a serving of all the meats on a bun (including a rib).

Dickey's, IMO, is the most consistent chain in Texas. Will never be as good as most independents, but reliable. I've eaten at many of them, and have never had bad 'Q.

Burbank's in Cincinnati, OH, was quite good many years ago, but quality seems to have fallen off beginning in the late 90's. I personally believe it was probably due to mismanagement and trying to aggressively grow the brand and open more restaurants too fast. All but the original have closed.

Finally, people seem to rave about Cousin's in Fort Worth, but I don't think it is all that.