Rudy's is a chain, but it sits around 10 in my list. Compared with the heavy hitters of one off Texas Barbecue -that ain't bad.
FYI - Salt Lick is 1, 2, or 3 on my list - just depends on how the barbecue gods are treating the venue the day I visit.
I've never eaten at the Goode and Co.'s places, but they do get recommended - good catch Georgetowngal.
Goode Company used to be one of the top BBQ joints in Houston, but they're still doing things the same way they did when they opened 25+ years ago, and IMHO, a number of places have surpassed them. Swingin' Door in Richmond isn't really close to Katy, but it's a better place. If you want brisket and are willing to drive to Goode Company, consider going a little further to the Brisket House. Here are the respective websites: http://www.swingingdoor.com/ and http://www.thebriskethouse.com/ I'd agree with Octoboy that, based on recommendations, Rudy's has a lot of fans (I've never tried it).
Killeen's BBQ, Pearland, Best around. Same level of the best in Austin and Hill Country. Brisket, T-Rex sized beef ribs. Go early. Sells out.
Gatlin's BBQ, Really good. Great Brisket and ribs.
Goode Company, Katy and Kirby. Very consistent. Doesn't hit some of the highs others do but come at 3pm or 8am and still very good.
Lulling City / Houston Barbecue Company(not same but split) Addictive mustard based bbq sauce)
Roegels Barbecue formerly Baker's Ribs, Galleria, Broken away to more craft brisket bbq
The Brisket House, Galleria, Good Brisket
Dozier's Grocery & Market, Fulshear
Guy's Meat Market, Near Astrodome. Go early lunch time for smoked hamburgers. Limited number (50?) made each day.