Musical theatre + choir= ?

I am going to a rehearsal of the Boston Children's Theatre show choir today, and I can't wait to hear them. Since I didn't grow up in the States I have never seen a show choir (except for Glee, but I don't think that counts). I'm hoping that what I know of musical theatre, plus, what I know of choirs, will make a beautiful mix and turn me into a show choir person. To continue...