Music to test with:

Pianorecordings, best one with a Steinway, the other a Boesendorfer or a Bechstein, Soprano arias, string quartets, a brass octet, a chorus, massed strings, or a nice slice of Berlioz' Requiem played at full tilt boogie are the acid tests I use to let a dealers face turn from chubby red to slightly pale. (-;
P.S. That is, if the dealer knows the sound of classical music. A rare breed indeed and an endangered species, but not yet entirely extinct. Cheers,

Same as Detlof above + lieder in mono. An old Dieskau is fine: can I visualise Mr Dieskau, his physical size, & the characteristics of his voice?
For the adventurous dealer, a tinge of Mahler 2nd symphony (1st & last parts) can also serve very well.

I just heard a really good cd for testing. It's by "Robert Hohner" and the album is called: "Far more drums". If you can, get the Hybrid Multichannel SACD version as the CD layer sounds much better than the normal CD version alone. The recording sounded better than all my HDCD's and was on the same level as XRCD.

here is a contrarian thought - instead of great sounding recording of music you love, use discs that you love but that have problems which can be excerbated by poor performing components, for example a disc with a high end that is almost too etched. if it sounds overly so (piercing) or underly so (dull) you will have easily discovered something. the problem with great recordings, is they will sound so good on so many components and you will be listening to the music and not the sound. i used to bring multiple cd's w/such problematic tracks. makes initial listening sessions much shorter.

here is a contrarian thought - instead of great sounding recording of music you love, use discs that you love but that have problems which can be excerbated by poor performing components, for example a disc with a high end that is almost too etched. if it sounds overly so (piercing) or underly so (dull) you will have easily discovered something. the problem with great recordings, is they will sound so good on so many components and you will be listening to the music and not the sound. i used to bring multiple cd's w/such problematic tracks. makes initial listening sessions much shorter.