For orchestra music, I generally prefer using film soundtracks over classical music. In my experience the quality of the recording is consistently higher.
Lately I've been using the "Lord of the Rings" (2001) soundtrack - it's a phenomenal recording with plenty of dynamic range in all frequencies and a wide variety of arrangement.
Have to agree. LOTR soundtrack is one of the best for this purpose. Also for fine tuning sub level in the receiver. Can't wait for the DVD this summer. Over 4 hours of film and music!
For orchestral music I use Holsts "The Planets" remasterred version by Deutsche Gramophone (Telarc also produces a copy). Not only is it good music (large dynamic swings, plenty of detail for a sound system to retrieve etc) but is a very good recording too. Film music is good too- Telarc's "Great Fantasy and Adventure Album" has some really intense selections, including a track with T-rex footsteps reaching down to 5Hz! Recommended.
Grab the second Moulin Rouge soundtrack, and play Bolero (the music from the end credits). The song is very diverse in it's musical styles, and a hell of a lot of fun to listen to.
Balero! Great song to test plus it's over 14 minutes long. It never gets faster as some think, it just keeps adding one instrument after another till your whole house is shaking, so don't crank it right from the start. That's it for a music review.