I bought a DVD set that has 15 episodes from an hour-long TV series that my family watched when it was new, "Riverboat." It starred Darren McGavin as the captain and Burt Reynolds as the pilot. We just watched the first episode and the theme music sounded so familiar. I learned through imdb.com that the theme song was written by Elmer Bernstein. Did he score some other TV western? Aha! The "Riverboat" theme from 1959 evolved into the theme from "The Magnificent Seven" in 1960.