Saving Private Ryan - Beach of Normanday
Saving Private Ryan, The Beach of Normandy, is one of my favorite demo scenes of all-time. It has absolutely everything you could want in a demo scene, not to mention movie. The was really well mixed. You have the explosions going off, that can literally shake the walls of your house, you have the gun shots going off, that will tell you if you have any issues with your tweeter. And then you have the background talking, during the bombs and gunshots. If you can hear that (not necessarily make it out), it can show an overall well-balanced response. But this is a great movie to test your problem areas.
It's a good one for showing off the Dinas for sure!
Disclaimer: I've been in the forum long enough to know a couple things, but have yet to actually do a speaker build myself =)