Speaking generally about my own experiences. I always got sucked into movie themes. This started with a lot of TV shows featuring the music of John Williams - GILLIGAN'S ISLAND, LOST IN SPACE, VOYAGE TO THE BOTTOM OF THE SEA, etc.
It was no wonder that when I bought the soundtracks to JAWS and STAR WARS that I was very familiar with his musical style.
Something else was happening at this time (70's - 80's). Repeated melodies in horror movie scores were very catchy. Of course these included HALLOWEEN (John Carpenter), PHANTASM (Myrow and Seagrave), SUSPIRIA (Goblin), A NIGHTMARE ON ELM STREET (Charles Bernstein) EXORCIST's Tubular Bells (Mike Oldfield), etc.
These horror scores usually didn't have the budget for an orchestra, so they used synthesizers. The "catchy" ones usually had a bell melody at the top end and a synth/string progression at the low end. So simple - a really high part (melody) and a really low part. Not much to muddy up the theme.
HALLOWEEN theme
PHANTASM theme
Then there are those directors who work with composers and gear scenes for the music. I've always loved this clip from CAT PEOPLE. Paul Schrader previously worked with Giorgio Moroder on AMERICAN GIGOLO. This is just magic - fast forward to the 1 minute mark and watch.
Irena's Dream
Recently, outside of Danny Elfman, I've noticed a shift from catchy themes to more atonal soundscapes. 30 DAYS OF NIGHT has a score that is a good example of that. I've noticed this with videogames, as well - SILENT HILL and RESIDENT EVIL are full of alien wind noises and slow metallic scrapings - or sounds that modern VAs (virtual analogue synths), like the Access Virus excell at. There is even a "Fear" setting that can be assigned to the Virus' control knobs.
I love good soundscapes and depending on the movie (NO COUNTRY FOR OLD MEN), you might not even need that much. Sometimes, the best music is no music.
After hearing a lot of forgetable scores, I'm finding myself quite drawn to the effective moods of John Murphy's music (SUNSHINE, 28 DAYS LATER). His music works in a pretty subtle way that seems to call to your primal emotions. In fact, the themes to those two movies were
reused for the movie, KICK-ASS and several commercials. His more recent 28 WEEKS LATER music was used for the first
AVATAR trailer
Just like the simplicity of the HALLOWEEN theme, Murphy uses a mix of guitar and synth. He doesn't jump around with a lot of themes, but he does suck you in with what he does use.
28 WEEKS LATER theme
And, the same theme as used here in the movie, KICK-ASS, which I really like.
Nicolas Cage kicking some...ass!
The uplifting
SUNSHINE music
I also like how it was used in KICK-ASS. Spoilers, if you haven't seen that movie! Theme kicks in 1 minute in.
Hit Girl To The Rescue
That's speaking as a soundtrack fan. I've also
composed many of my own scores. I often go with
a hybrid of synths and orchestral tones. When I have time with a project, I will usually spend a week or two just putting together a palette of sounds together. Sometimes the bad guy gets his own sound, like a rolling hollow styo tube that I used for an old score.
I made
one teaser, where I programmed a low bass sweep, which broke up the orchestral sounds and it worked well to establish mood. I think sounds can be as important as the composing, such as Steve Jablonski's synth sounds that come in and out of his TRANSFORMERS score. The movies may be so so, but the music and sounds are awesome to the point that they can "make" the movie, for someone like myself.
The first thing to decide is what scenes need music and which don't. Often, a director/producer will ask you to take a weak movie and amp it up. So many times, the composer is asked to save the movie. That's a tall order. (John Carpenter admitted this was the case with HALLOWEEN and it did in fact work!) Other filmmakers are more confident and meticulous.
Once you decide which scenes, you must decide on style and sounds. Is it going to sound pop/rock, orchestral, synthesized, minimalist, etc? Are you going for an organic background approach, where the music mirrors pace and actions; or is it going to be more in your face, Quentin Tarantino style? Again, a lot of this depends on the producer's preferences.
Is the main theme going to be a motif that is heard in other songs? Does each character get a theme - hero's theme, love theme, bad guy's theme, etc.? You really need to just watch the movie several times and feel your way through it.