Great thread idea, Filper, but only one? I can't even eat only one Lays potato chip!
Considering Filper asked for a surround demo and not a favorite song, I'd likely ask the uninitiated to sit in the sweet spot in my living room and listen to "Yoshimi Battles The Pink Robots Pt. 1" simply because after having listened to several great surround titles, my jaw hit the floor when Scheiner made the acoustic guitar jump from speaker to speaker. It's probably the most aggressive DVD-A I've heard to date, but then again, the 2 Queen titles (Bohemian Rhapsody, anyone?) and Beck's Sea Change (Golden Age) also make the grade, albeit in a slightly more subtle way.