I usually attempt to steer clear of trailers since nowadays they seem to give away far too much of the film, but in fitting with my new sig/avi set the Alien and Alien 3 trailers/teasers are great:
^ How does that not get you hyped? Best teaser of all time.
^ There's better trailers than this but I love the old school feel with the voiceover and THE BITCH IS BACK. Not to mention that shot of Ripley and the xeno at the end is one of my favourite shots in cinema history. It probably works even better in the trailer than the actual film since it's a superb way to end the trailer on a cliffhanger and leave people wanting more.
OP you made me sad because the VOICE OF TRAILERS just died and this thread reminded me of him.
Check out the pilot for my webshow WISHFUL THINKING. It is a show about a college student who fucks up his day and a Genie grants him the opportunity to do it all over again and he finds new and creative ways to fuck it up even more.