Oh wow.. i've seen CATS, Fiddler on the Roof, West Side Story, Phantom of the Opera, Les Mis, Joseph and the Amazing Technicolour Dreamcoat, Riverboat, Miss Saigon, Mama Mia, Beauty and the Beast. I'm sure I'm missing some, however that's all I can think of right now.
As for my fav? Hmm.. that's too tough to answer. Phantom, Mama Mia, Miss Saigon, Les Mis, Joseph were all in the top I'd say.