What is your "evaluation cd"?

Herbie Hancock: "Future Shock" (dynamics, fluidity, drive, air)

Magma: "Udu Wudu" JVC 20bit (dynamics, transients, tone)

those are the first two I always go for.

Lisa Loeb "Firecracker" - binkie music but extrememly natural recording. Also, has several "tasteful" 360 degree sound effects, as well as a well-recorded door slamming.
Wagner/Solti Ring on latest Decca CD - great music, best recording of strings esp. basses, anvil striking great test of amplifier clipping even at low levels.
SACD - the SONY sampler

I've used Jakob Dylan's "Bringing Down the Horse" because until recently, every upgrade removed some hash but still sounded noisy and distorted unnaturally at some places. To be specific, there are times when a highly distorted electric guitar is playing LOUD, and in the background, at very low levels, are a chorus 'oohing', coupled with high frequency synth, coupled with sticks on the rim, coupled with a high hat. The problem is all those faint high frequency parts can and will mush together with a low resolution system. To discern these different parts, I use a Monarchy DIP balanced connection to a Nelson MSB DAC with 24/132 upsampling and Power Base, as well as Monster Power HTS 2000 and numerous Quietline filters.

I took a lot of my favorite tracks and compiled them on one CDR, with a bit of everything from solo piano to some heavy electronic, it's really useful especially if you go to a dealer to listen. I can just pop in one CD and get an idea of what a system sounds like with a big variety of music.

When I am interested solely in evaluating an audio component, or doing an A-B comparison, I frequently use the Burmester CD#2. Otherwise, I have a group of jazz and symphonic LP recordings that I have listened to for years and know all of their nuances.