LOL~! I don't talk during and throughout every movie. Also, I try to make sure I'm not talking over movie dialogue. I mostly make short comments, like just a couple of words at a time.

I'm not inconsiderate; when I know the person/people I'm watching a movie with don't like that sort of thing, then I won't do it. But it's my preferred mode of movie-watching, so I enjoy movies more when I watch with someone who's the same. =D