Great Demo for music/surround Eric Clapton live on tour 2001, select DTS and stand back....AWESOME!
I have that DTS sampler and it is great.

I like to go with something like
Dada: Puzzle = a few good tracks on it. esp. #1
Eric Clapton: unplugged = Layla.
Diana Krall: Damn near anything!!!

But in the end we usally ask our customers to bring in one or two of the disks that they already own, music that they know, so they can tell how much more music there really is on the disk that their current system isn't giving them!!

Anything by Mannheim Steamroller. They became famous from their Christmas music... but before the Christmas stuff, they produced fantasic stuff for demos. Check it out.

Letting a customer bring in their own is always best, but it pays to keep a good selection of different types of music on hand. I have a couple of disks I've created for demos, but I keep about 30 CDs of various stuff for people to choose from. This is the track list of a disk I burned for demo purposes a couple of years ago that is the primary one I use:

Allman Brothers - Whipping Post
Guns N' Roses - November Rain
Shaniah Twain - Don't Be Stupid
Jewel - Foolish Games
Top Gun Anthem from the Top Gun Soundtrack CD
Joe Satriani - Summer Song
Led Zeppelin - Stairway to Heaven
Stevie Ray Vaughn - The Sky is Crying
Leo Kottke - Jesu, Joy of Man's Desiring (Bach)
Cherry Poppin' Daddies - Zuit Suit Riot
Pink Floyd - Time
Coolio - Gangsta's Paradise
Celine Dion - My Heart Will Go On (Okay, it sucks but it helps to sway the wives now and then.)
Metallica - Unforgiven

You folks must sell to a bunch of young dot-comer's because there is very little classical and jazz in your selections. If you ever have clients over 40 that are audiophiles, I suggest you add a few bold classical and jazz discs. For the later, I rely on the "Yellowjacket-Four Corners" (extremely well-mixed) or the first Getz-Gilberto album.

DTS demo DVDs are all over EBAY...check seller's feedback, some clowns are selling DVD-R copies.
DTS #4 is great
Ureleased DTS is also a great demo

Lucky Man by Emerson, Lake and Palmer on the DVD Audio disc Brain Salad Surgery

Journalist, I was happy to see that you said let the customer decide. I don't care how much an installer may think they know their customer but I'm certain that the odds are very low that your high-end customer is going to be impressed with Guns-N-Roses. What a great way to ruin your reputation in an instant.

When in doubt leave the hard stuff out.(Even if you don't think it's hard) You can work your way up slowly as you acquire the customer's taste. I once saw a guy crank up Howard Stern as soon as the tuners were up and running! What the hell is that? Do you know how that will change an NPR listener or a Jazz buff's opinion of you and whether they're going to refer you to a friend?

Of course if all of your customers are the same white-trashy-trailer-parky-Wrestling-Loving-Got a spot next week on Jerry Springer-It's Ok you can spit your chew in that paper cup there-You might be a redneck Type of customer.... Well then crack some beers and fire up the Guns-N-Roses!

I'm afraid your awareness of the necessity for a wide selection of demo music isn't shared by all.