I am a big fan of film music, and have even dabbled a bit here and there doing music for film in a few different capacities. In fact, I have a chapter on film music in Rob Johnston's book, Reframing Theology and Film, which draws together a number of thinkers doing stuff around various aspects of film. Music in film is a bit like the Holy Spirit, often the overlooked member of the trinity. Meaning in film doesn't simply come from dialog or narrative but from a trinity of meaning makers: story, visuals, music, each of which contribute to the overall meaning-making process. I would argue that music plays an incredibly important role in film and always has, even in the 'silent' film era, it was only the film itself that was devoid of sound, most, if not all movies, were accompanied by music, organs, pianos, chamber orchestras, all supported the celluloid tales and gave life to what was happening on screen. All that to say I came across a great blog called The Playlist, which is dedicated to music in film. It's a cool site with great posts and views. The first post I came across was a bit of a rant about the tendency to use music created for other movies in new film trailers, you've probably seen a few yourself. Hence the title of my post, which is the name of a piece of music by Clint Mansell which was created for The Fountain but which now shows up in the new Will Smith movie trailer for I Am Legend. This tactic is something I personally find a bit irritating, even though I think I understand the rationale behind it--economics, ease, proven emotional arc etc. anyway, if film music interest you this site will be a frequent place to visit.