Another digging-through-old-CDs-rediscovery moment:
Elton John - Tumbleweed Connection. I've been listening to this one a lot lately. It's very well recorded, but I never noticed how well until I had the Salks. I'd vote for the track, My Father's Gun, as being a good demo. Good dynamics and separation of instruments, and at the risk of sounding like a broken record about Jim's speakers, very clear, detailed vocals.
Happy Listening,
Mathgeek97