I am digital only, and right now my first choice would probably be Cowboy Junkies?Trinity Sessions on my (I think, Analogue Productions) SACD.
I would also use my MFSL SACDs of Dire Straits self titled or DireStraits/Love Over Gold (particularly the first track).
I have four different digital pressings of Patricia Barber/Cafe Blue, and I'd probably use one of the two SACDs of that.
The problem with that, however, is that I have found if the listener's taste in music varies from what I've picked out, it is not all that effective of a demonstration. Steve Earle/Train A Coming used to be what I considered to be some of my best digital, but I remember playing my favorite track for a friend of mine, and he was pretty much disinterested.
Anymore, I'd probably just suggest that someone brought their own stuff over . . . and see how it compared. The last time I did that, my friend was blown away. He said something to the effect of: that he was depressed because we both had the same speakers (B&W 805s) and mine sounded so much better.