Agreed. West Side Story is the most fantabulous musical ever. My other favorite is Into the Woods. Has anyone else ever heard of it? It's not really popular, but it's recieved some publicity and got a few awards... It's sort of a combination of lots of fairy tales, but woven into one coherent plot, with great music and an even better storyline. My High school performed it a few year ago (I'd never heard of it at the time) and I couldn't believe how great it was. It's a bit long (3 hours with scenes cut out), and the second act is rather depressing, but you should try and see it any way you can. My sister has a DVD, but honestly I thought that the singing was a bit sub-par, compared to when I first saw it. At that time, my high school had an AMAZINGLY talented group of Juniors and Seniors, which made the show all the more memorable. I think like half of them are drama majors now, or something...
But whatever. Into the Woods. Go see it.
Singing in the Rain is a great one, too. Haven't seen Les Miserables yet, but I'd like to.