I just finished an extended stint in Houston, and on recommendation of FT'ers Premex and TXHolly, I went to Baker's BBQ (a.k.a. "The Pig Place").
Each of the last three weeks I've been there, and feel its in my top three list nationwide. The pork ribs and meats are great, as our the sides. The added bonus is very low prices. Pork ribs with two other meats, and two sides, is $9.95.
Easy to find, its ten minutes from the Galleria, on Voss just south of San Felipe.