I dunno. I'd prefer it if I could:

a) See trailers for movies coming out further in the future than this week, and

b) Rate the trailers before the movie comes out (and more to the point, see what other people think of the trailer of as un-yet unreleased movie)

You could have two forms of voting: until the movie comes out the question is "What did you think of the trailer" and after it comes out it switches to "Was the movie better than the trailer?"