I no particular order...

Madonna-
Immaculate Collection

I like this album but it tends to make every system sound good, so it's not really a good reference recording. It is very well recorded though.

Metallica-
...And Justice For All

Wicked double bass drum, great music, but one of the worst recordings in history

Black Album

Ear candy.

Diana Krall (anything by diana krall) Beautiful voice, best recordings on the market. Excellent stereo seperation and placement. Listen on a good reference system and you'll be able to place her at a particular point, not a general area, but a defined point. Probably the best reference recordings on the market.

of course Telarc's 1812 overture as a woofer tester...