I've actually been wondering this very thing myself. We've discussed this before, and there is a war movie that was recommend by just about everyone for the opening scene of battle. And it is not just that the scene is loud, but that the sound quality is very crisp and detailed as well as powerful.
It was -
Saving Private Ryan
Or
Flags of Our Father
Or
Something similar.
But I can't remember what. Maybe some who remembers that old thread will come along an enlighten us both.
Myself, given my limited collection of videos, I always play the Voldemort/Dumbledore Ministry of Magic Duel from Harry Potter and the Order of the Phoenix. This scene has a lot of complex sounds in it, dialog, roaring flames, flowing water, tinkling glass, explosions, as well as the snap and crack of spells being thrown.
Still would like to know what that war movies is though. It was recommended by several people in the discussion, again, not just for its intensity, but for the absolute clarity of the sounds.
Steve/bluewizard