Having lived and travelled all over, I can offer that BBQ sauce is BBQ dependent and different around the country.
My fav for Memphis BBQ and ribs is Rendezvous from the famous Memphis restaurant of the same name. It is in an alley and just across from the Peabody hotel. Highly recommend both if you find yourself in Memphis or just passing through.
A lot of the famous Lockhart, Texas bbq joints only started offering sauce in the past 15 years or so. Prior to that they just gave you Texas Pete and white bread. Lockhart is the Texas Capitol of BBQ about an hour SW from Austin.
My fav Kruez used to only give you Texas Pete and you had to bring a pocket knife if you wanted to cut something.
And don't forget about Alabama white sauce:
