I wouldn't say it is one of the greatest openings ever, but it is one of the few openings in a movie to just hook me into wanting to know more about what is happening: Paprika
I also really like the opening to Hugo
, where we are entering the train station and just sweeping through it giving a look at the world presented and the characters within it. It's really breathtaking.
Though I am really offended by you people. Not one person mentioned the opening to Jaws