Children of Men was better than I thought it'd be.
See, I have this love-hate relationship with science fiction movies. I love science fiction. I hate science fiction movies. They always get it wrong.
Science fiction is about extrapolation. You start with "what if?" and you work from there. The complications need to tie into the world, what makes it different from the real world, what makes it science fiction.
Otherwise, it's not science fiction. If it could work in a different setting--if your story is "a western, in space," it's not science fiction. It's got the trappings, but not the mechanics.
Note that this doesn't mean that shows like Firefly aren't science fiction. (I use "western" because it's traditional, when making this particular point.) Firefly is actually an example of the reverse of this phenomena. It's got western flavor, but develops its plots in a science fictional manner: pick an aspect of the setting, figure out how that aspect could cause problems for the protagonists.
Science fiction movies--or rather, the movies people call science fiction--don't generally do this. Or they don't do it well. They tend to be too concerned with blowing things up and making philosophical points.
The Matrix is an example. I loathe this movie, with a totally unwarranted passion. And I mean the original, not the latter two--haven't even seen the third. People think it's deep, and they think it's science fiction. It's not. It (or rather, it's hack writers/directors) starts with a philosophical point it wants to make, and then puts together a patchwork setting that exists only to make this point. It's got no depth, except for some idiocy about vitamins. And that doesn't even count, because it was old hat when Asimov was writing robot novels.
I guess that's what I like about Children of Men, at least now, before I've had the chance to really think about it. It's got depth. It's got a number of different challenges and plot twists, all based on the setting. It brings up things that are never fully explained ("your parents were in New York when it happened") because they don't need to be, but they still make sense.
It's got a sense of verisimilitude. The story comes from the world, not the other way around.
And I liked the music--felt all future-y without being stupid, and there was a lot of Beetles, which made sense in the context of the world.