I saw a scene from "The Line-Up" recently and the first thing I see is a 38 Geary bus. It doesn't get any more SF authentic than that. Runs from deep in the Financial Dist to Ocean Beach. The only other lines with as much Creed are the 22, 15 3rd, or the 30 Stockton which has a starring role in the Great Great SF Police Drama "The Laughing Policeman" starring Walter Matthau and Bruce Dern. Drop everything and see that film.