Right... themes on top of my head...
Secret - LeChuck's Theme
Revenge - Scabb Island Map
Curse - uhm... uuuhh... eeeehhh... I caaan't really remember anything... Monkey Island Theme? (MI2 has my favorite MI theme though)
Escape - Lawyers Music
Tales - The Screaming Narwhal map music (that is prominent in Chap2)
Most favorite soundtrack - Escape (I think I'm really fond of each and every music sequence there... well, at least 90%).
Least favorite - dunno. I can say that I like Tales music less than it deserves because even non-SE-SoMI/LR music may actually sound better than it. Though some tunes are just great.