To me, the first trailer for Lady In The Water was stunning in terms of the atmosphere it set. The dreamy, incomparably beautiful violin, the ordinary scenes of everyday life, and then...the promise of an ordinary life changed forever with something mysterious moving in the water outside. I still get chills when he whispers at the end "How many of you ARE there?" It's a shame that the trailer promised so much more than the movie could ultimately deliver.
http://www.apple.com/trailers/wb/ladyinthewater/