Terry Teachout's always estimable About Last Night features a quick look at a favorite topic of mine today - film music. He maintains within that "Generally speaking, a score is something you shouldn't notice until the second time you watch a film. If the score jumps into the foreground on first viewing, it might mean the film isn't good enough to hold your attention."
I'm not sure I agree. He's positing the theory as a generality to begin with, to be sure, and for many folks the score is just an ancillary part of watching a movie, something that works its magic without you noticing. But many people watch films closely, both noticing, on some level of concsiousnes at least, supporting elements like music and lighting and being affected by them. For those folks, the score always jumps out as a tangible element.
In any event, here's a quick list of some of my favorite film scores. Please note that this list is in no way meant to be definitive; I'm hardly a film buff and, as recently noted, am woefully uneducated about the world of film older than I. So that I'm missing just tons of wonderful film music is a given.
I tend to get myself fixated on composers, so here's the best of the bunch I tend to listen to:
Meet Joe Black
Crouching Tiger, Hidden Dragon
Again, just a handful.