I was not very impressed with the surround effects in Gladiator. Do not get me wrong. It was an excellent movie. Just does not have the impact for a demo. Surround effects are much better in movies like:

Lord of the Rings (Extended Versions) DTS 6.1 tracks - Any of the many battles
The Incredibles - Chase scenes on the island
Pirates of the Carribean - Fight scene with the black pearl
Bad Boys II (Superbits DTS track) - Car Chase
The Grudge - All scenes with little boy running around
Harry Potter Movies - Any Quiditch scene
Finding Nemo (Full Screen Version) - THX Intro with flying robot