I have very obscure taste in music, and even I can't get my head around what's in Bart's CD Cellar. It was Bart's that turned me onto Esquivel, Four Tet, and Lemon Jelly. Need I say more?
Just ask - you can listen to anything in the store, and they have a great used CD collection. I don't buy vinyl, but they evidently have a great vinyl collection upstairs as well.