It's all a matter of taste I guess, but I've been playing these a lot:
Lights (The Listening)
The Who (My generation, US compilation: Won't get fooled again, preferably)
Keb' Mo (Keb Mo)
Loudon Wainright III (Strange Weirdos)
All make good demo sessions IMHO. I suppose the danger is that you play your fave tracks and they sound great on any system. But I think a new system should make you want to strut around, or weep depending on track, if you play your faves. Otherwise, stick with what you've got.