Some of the classic "panning" scenes are in the DTS versions of Casper and Dragonheart.
Casper has very good panning throughout the movie, I think the new DTS demo disk at CES showed the scene where Ricci went through the automated "get ready" ride.
Dragonheart has a nice scene where the dragon flies circles around Quaid saying something about the "old code".
Those were my reference tracks, at least in the days of laserdiscs.