If you find yourself losing faith in the subtlety of film music, allow me to suggest a few composers with restorative powers. Like the couple in a recent New Yorker cartoon who stroll unwittingly from the pastures marked "rock" through to "pop" and then "easy listening" (caption: "They never even knew"), the once-intriguing Danny Elfman, a regular Tim Burton collaborator, has lapsed -- perhaps irretrievably -- into mediocrity.

But Carter Burwell is still on the money. Burwell is best known for his work with the Coen brothers -- he's scored every one of their films, from 1984's Blood Simple to last year's A Serious Man.

My favourite scores of his can be heard in Rob Roy (this is how good he is: he makes Celtic pipes palatable), Adaptation and especially Before the Devil Knows You're Dead (where Burwell was called in at the 11th hour to replace another composer's score).

I was going to add The Hi-Lo Country: I can still hum that one despite not having seen Stephen Frears's film for over a decade. But on reflection, it's not a good fit. It's very grand and rousing, whereas those descriptions don't pertain to anything in the characters or story; you can't tell what the music is expressing.

It's not Burwell's fault, nor is it a slight on his work. Pure speculation alert: I wonder if the music was brought in once everyone realised that no one in the movie was particularly heroic, nor did they want to be. The idea may have been to get the audience excited, and hope they wouldn't realise until they got home that there was nothing on screen to be excited about.

Surely a fundamental rule of any score is that it has to have a correlation to what we're watching; otherwise it floats free of the movie, and can be as incongruous as an unnatural light source or a visible boom mic. Stuart Staples of Tindersticks has done some incredible work for Claire Denis, including her new film White Material (which I review in the next NS).

Check out the Tindersticks' score for Denis's last film, 35 Shots of Rum, where it ebbs and flows in gorgeous synchronicity with the performances, camerawork and editing -- a model not only of how to compose great film music, but of how to weave it into the action.

I also rest easy when I see on the opening credits of a film the names Alexandre Desplat (best scores: Birth and Lust, Caution) or Mychael Danna (The Ice Storm, Capote and 8MM -- the latter a classic case of great score/dud movie).

A contender for the finest film music of this year is the score for A Single Man, Tom Ford's adaptation of Christopher Isherwood's novel about a gay professor in early 1960s Los Angeles, mourning the death of his lover. (The film has just been released on DVD.) I should clarify "finest" by explaining that this score seems to emerge fully and organically from the movie, with no suggestion that it wasn't in fact generated spontaneously by the images, or vice versa.

"The music was an extension of George," Ford told me last year.

I was thinking about it as I was writing and shooting. Violins I knew I wanted to be prominent because they're the most human instrument; they can convey the most incredible sadness and also joy. Shigeru Umebayashi, a brilliant Japanese composer, wrote three pieces; he works with Wong Kar-Wai a lot, he's incredible. And Abel Korzeniowski is a Polish composer in Los Angeles, he's also incredible: he scores not just action but emotions. That's a crucial device in helping the audience know what George is feeling. Abel is the difference between someone scoring and just composing. When I was working with him, I was saying, 'This is great, but I need more.' And he said, 'More? Usually I get asked for something that just goes away into the background.' That's incredible! Why have music that just fades away, fills space?

"Often a finished film can be a slight disappointment," Firth chipped in,

or it might go off in a different direction to the one you'd anticipated. But the musical choices in A Single Man conformed to what I felt the film should be. Very rarely have I heard music on a score that reflected what the film felt like to make. If the music is an extension of George's thoughts, then it's bang on. It could not be more right. When I heard it for the first time, I had this strange idea that I'd sung it or something because it felt like it had come out of the character. To feel that this was what Abel was doing, following the thought processes of the character -- well, that really made sense. I want to meet this guy, because I really feel like we worked together. And you almost never feel that.