I agree that it is essential to use music you know well. Some of my favorites are K.D. Lang Ingenue, Eric Clapton Unplugged, Toni Braxton and Jerry Lee Lewis. I also agree with Drewfidelity that you must try different kinds of music as to get the full capability of the equipment with different music.
Which CDs to test a component?
What CDs do you like using to test new components?