I tend to prefer working with trains and regional-scale transport, as setting up and mantaining bus lines seems more like micro-management to me, so I set station-coverage to 8 or 10 (don't remember exactly) ad use buses only occasionally, mainly to reach city areas distant from the stations. For mid-sized cities, when bus lines are not enough, usually I lay a circular tram line. In larger cities I use either underground or overground "S-lines" if the city develops during the game around tracks I already built.
