West Side Story, of course. Provided they give me a bass sax to play. (And provided I could still play, that is.)
There are a whole lot of musicals I wouldn't mind singing for -- again, provided I could walk around the stage for the entire show without keeling over -- but I've not really known too many musicals that have an excellent score that are just wonderful to play. It's mainly just good accompaniment for the singers. Just an observation.
EDIT: you mention Avenue Q. A lot of good songs in that one.
Yes, I'm the Artist Formerly Known as Saxpics.
If you need me or just want to chat, e-mail me @ thesaxinfo-at-gmail.com.