These are some I have loved.
Star Wars: Battle of Fates (The Phantom Menace), and Vader vs. Obi-Wan (Revenge of the Sith) - Got to be some of the most exciting pieces of music ever created in cinema history; completely amazing with the moments it plays at. (The battles)
Lord Of The Rings: The Shire (Fellowship of the Ring) and March of the Ents (The Two Towers) The first piece is beautiful... peaceful, and it's simplicity in it's creation only adds to it's artistry... and the March of the Ents... wow, I loved the vocals, the way dozens of gaint powerful creatures watch on Isengard. Amazing moment.
Titanic: Sad, yes... but I found I loved some of this music greatly. The tunes in it are largely sad and heart wrenching. The music when Titanic firsts gets going and Jack(?) screams at the front of the ship was great as well.
The Matrix Revolutions: Neo versus Smith. Wow... just... wow

Overall, I think I'd say that classical music in the cinema was what first made me really appreciate classical music outside. With classical music, it's so music easier to discern and inform what mood you are being portrayed, or portraying.
So what are yours?
