I used to use the 2nd "army attack on Godzilla" scene of the Matthew Broderick movie as a surround sound demo scene.
No foul language and no blood and guts, but great for hearing deep, wall shaking bass and bullets, guns, missiles, helicopters, etc etc.
I had empathy for the Godzilla in that movie, and felt sad when.....well, I won't spoil it for anyone who hasn't seen that one yet.
I use the scene from Iron Man 2 when he flies into the convention with the dancing girls and the fireworks going off to demo my home theater. Lots of bass and pretty girls dancing. I don’t have 7.1 like you do, but 1,000 watts into a Sony 5.1 really rocks the room. 125” diagonal is just the right size.