Texans are pretty serious about BBQ and so far, Rudy's has been my favorite
http://rudys.com/
Goat, I can only assume that some non-Texan has illegally gained access to your acount. It's ok, but there are so many others.
To answer the question of the OP, for stuff you can buy, Stubbs is probably the best BBQ sauce.
The absolute best comes from a place called Oklahoma Joe's in Kansas City (go figure). They used to sell their sauce through mail order, but now it is only available at the restaurant, which is inside a gas station.
As for BBQ shops in Texas, I have three recommendations.
1. The Legend: Marshal's BBQ in Dallas (actually located in Farmer's Branch and Carrollton)
2. A classic: Lawrence's BBQ in north Austin
3. The ultimate: Unnamed location at the corner of FM-39 and FM-977 in SE Texas. In the summer months a guy sets up a shack and sells BBQ on the roadside in front of his property. He has claimed that he raises and slaughters his own beef, but I cannot backup this claim. If you're ever in the neighborhood, do drop by.