With regards to musicals, I don't have a terrible lot of albums, but the ones that I do have get very good use. Again, this is only a partial list, but off the top of my head, I have...
Hedwig and the Angry Inch (both the original Broadway cast recording, and the "Wig In a Box" tribute album)
Hair (both the original American cast and the original German cast)
1776 (the new cast with Brent Spiner)
Brigadoon (original cast)
EFX (Vegas show with Michael Crawford)
Batboy the Musical
The Full Monty
Jekyll & Hyde
Phantom of the Opera
Phantom (another musical based on the same book, but done before Andrew Lloyd Weber's show came out)
Rocky Horror Picture Show
Notre Dame de Paris (both the American and French casts)
I've also got quite a bit of what might be called "easy listening", from Sarah Brightman to Bing Crosby and Jimmy Durante. There's also quite a bit of folk music and classical recordings in my collection, from Holly Near and the Righteous Mothers to Salieri. If you want to know whether I've got a particular album or not, just ask--I just might.
Anyhow, I'm looking forward to hearing from folks! As to what I'd like from others--surprise me! I love themed mix tapes, both making and receiving, and greatly enjoy discovering new pieces to listen to.