Well, I was running Karazhan on my mage, and she received a music roll from the opera event!! It's a little out of place in the garrison, but I love it, haha.
Anyway, here's the Garrison Jukebox guide from Wowhead: http://www.wowhead.com/guides/garrisons/jukebox
I have a new thing to be OCD about, and I can't even blame Maltz for it. >.<