Despite what the supporters of Forrest Clare “Phog” Allen, Adolph Rupp, Dean Smith or Bobby Knight say, John Wooden is truly the greatest college basketball coach of all time, no contest. This is because of Wooden’s amazing championship runs at UCLA.
Oh, I don't know; I think it depends on what you mean by best coach. He won a lot of games, for certain, but he didn't contribute much to basketball in terms of changing the game, and he doesn't have much of a coaching tree. I think it's also fair to raise the Sam Gilbert issues, as it is certainly worth noting that Wooden was at UCLA a long time--never winning anything--until Gilbert showed up.
Greatest "coach," at least in terms of changing the game, has to be Hank Iba. The guy invented the motion offense, which is used by nearly every organized basketball team in world. He perfected man-to-man defense, and has a coaching tree a mile long.