The Secret of Monkey Island is one of the greatest games of all time, representing a rare gathering of creative talent including, among others, Ron Gilbert, Tim Schafer, Dave Grossman, Steve Purcell and Orson Scott Card. Included in that number is Michael Land, who composed the game's fantastic Caribbean-influenced theme.
Land went on to collaborate heavily with Lucasarts between 1990 and 2000, working on the scores to the subsequent Monkey Island games, X-Wing, Tie Fighter, Indiana Jones and the Fate of Atlantis, and The Dig.
The version above is the mt32 MIDI mix of the main theme, as played during the opening sequence of the game. The later CD edition of Monkey Island came with several bonus audio tracks, notably an excellent rock remix of the theme which unfortunately does not seem to have made its way to YouTube.