As far as that particular battle scene goes, my favorite moment was when Eowyn said (from IMDB):
Witch King: [taking Eowyn by the throat] You fool. No man can kill me. Die now.
[Merry stabs the Witch King from behind; the Witch King shrieks and falls to his knees. Eowyn rises and pulls off her helm, her hair falls down over her shoulder]
Eowyn: I am no man.
[she thrusts her sword into the Witch King's helm and twists; he shrieks and implodes]
_________________________
The trick, William Potter, is not minding that it hurts. The trick, William Potter, is not minding that it hurts. The trick, William Potter, is not minding that it hurts. etc . . .