The most poignant, powerful moments of the film. (Spoilers)

[Kitanna]

The moment that makes me cry every time is when the mother in Rohan puts her two children on the horse so they can raise the alarm in Edoras. Children should not be ripped away from their parents!
When Frodo destroys the Ring I can't even begin to put into words how that makes me feel. I think it's the music that's played that really gets me.
But the most moving part in any of the movies is when the Riders of Rohan arrive at Pellenor and charge down at the Orcs. Theoden's line gives me goosebumps. "RIDE NOW! RIDE NOW! RIDE FOR RUIN AND THE WORLD'S ENDING! FORTH EORLINGAS!" And the music in the background is so powerful. Sigh, so cool...