I love Andrew Lloyd Webber's stuff. Although I don't think it was ever a big hit, his Aspects of Love is my favorite music ever, and I would kill to see it onstage. I also love Evita.
Other non-ALW favorites are Miss Saigon (seen onstage in Florida), Into the Woods, and Chess, which I've seen a small production of. Oh, and Les Mis, which I've seen twice.
Musicals I've seen performed:
Les Mis (Boston)
Phantom (Boston)
Jekyll and Hyde (NYC)
Miss Saigon (Orlando)
Oklahoma (local professional)
Into the Woods (local professional)
Sound of Music (local professional)
Guys and Dolls (local professional)
Chess (high school)