I'll second Baker's Ribs. I used to to eat at the Greenville Ave location about once a week when I lived nearby. Hope you get a chance to check them out. Sonny Bryan's is way overrated, but it's typically the place that gets all of the press in Dallas. Steer clear of the chains like Spring Creek, Colter's, Dickie's and Red Hot & Blue. Bone Daddy's would be my second pick in Dallas, but they can sometimes have an off night on the pit.. If you're close to Ft. Worth then give Risky's a try. I haven't been there in years but the one in downtown used to be great for a chopped beef sammie.
~Dave