A movies introduction or opening scene is very important. It sets the scene and tone for the movie, if done well it can excite us and leave us in anticipation for what's about to follow. Here are some of my favourites. What intros appeal to you, that get you in the mood and looking forward to the rest of the movie?
The Zombieland intro is just awesome, the slow motion shots of the beginning of the zombie attack with Metallica playing really sets the scene well.
Idiocracy is a very funny satire, the opening scene explains the premise of the movie and is very entertaining while doing so.