I'm genuinely surprised this one hasn't been mentioned yet--although I guess, at this point, it might be a bit cliche. However, I still think it's one of the best scenes to demonstrate just how much emotion and power the right music can give to a scene.
I don't want to write the special code here as an example and accidentally trigger the command, but you write youtube inside brackets.
Easiest way to see it for yourself is to click "Reply" on my Avengers comment and then looked at my quoted text. You'll see the special embedding code in my quoted text.
So, so many scenes to choose from, but here's one of my favorites, mainly for how it connects this scene to prior ones, and how it is a musical culmination of previous threads and story elements in a grand, majestic fashion:
Ive got one. Waxman's Ride To Dubno as the cossack army builds as all the various clans join up with Taras Bulba. As more cossacks join, the music keeps swelling. Superb. Proper epic, no false cgi, with real people riding at the gallop, not easy to film.