West Side Story is definitely the best ever, followed closely by The Sound of Music. For a modern take, if you allow for animation, Frozen really is fantastic, albeit very overplayed. If you don’t care for musicals, you’re missing out! Hollywood has the right idea to bring them back. There is actually something special about people breaking into song to drive the point home, even though they’re really not advancing the story. It gives the viewer time to just enjoy the moment.
Hedwig and the Angry Inch. One of the best stage musicals and it transitioned beautifully to a film, very different from the stage version, but a brilliant kind of different. Having the co-creator be the star and director, bonus. See it! And see it on Broadway too if you can.