I think some of this topic has come up before within other contexts. For me:
The whole Star Wars series, with Empire probably being my overall soundtrack favorite, though there's great stuff in all of them.
The Indiana Jones series, with Raiders as the favorite (the Ark theme is amazing).
Conan the Barbarian, an incredibly good score by Basil Poledouris.
The Black Hole by John Barry (probably just about the only redeeming quality of that film!
).
Titanic I agree on; that stupid song got overplayed to the point of making it sickening, but it
is a very good score.
The whole Lord of the Rings series; great work by Howard Shore.
Schindler's List; John Williams shows great versatility with a very subtle, emotional score.
The Crow; "Burn" by The Cure is worth the price of the CD by itself for me, and I'm not even a fan.
The Terminator by Brad Fiedel (and to a lesser extent T2).
A Clockwork Orange; great work by Walter/Wendy Carlos, especially the opening title adaptation from music for the funeral of Queen Mary.
The Last Temptation of Christ; Peter Gabriel's Passion album is
astonishing.
Rabbit-Proof Fence; same answer!
2001: A Space Odyssey; I thought the use of György Ligeti's Requiem during the Monolith scenes was genius.
And while it's not a movie, I'd say Christophe Beck has done some of the best scores I've ever heard with his work on Buffy the Vampire Slayer (particularly seasons 2 and 3, and the last episode of season 5).
That's all I can think of for now. Man, I'm a geek.
Blake