I just learned via Woman’s World Magazine via my sister that the theme song from Gilligan’s Island that I know and love was not the song used in the first season. I’m sure you know the later song, so I won’t remind you. (You can find it at metacafe.com if you need a refresher.)
According to the article, Bob Denver (the actor who played Gilligan and Maynard G. Krebs on The Many Loves of Dobie Gillis) was responsible for the change. In the first season, Russell Johnson (“The Professor”) and Dawn Wells (“Mary Ann”) were not in the opening credits and the song ended with “and the rest” rather than “the professor and Mary Ann.” Denver requested that this change be made, but the studio refused, saying it would be too costly to change the song and opening credits. They relented when Denver threatened to force them to put his name at the end of the credits—which he could demand by his contract. Thus, Johnson and Wells not only got included in the song, they got on the opening credits.
You just knew that any actor known for playing Gilligan and Maynard G. Krebs had to be a good guy!