TOD: I love the fact that many DVDs of classic films are including the trailer, so you can see how some of th ebest are made. I think I like any of the lurid trailers for film noir classics like "Out of the Past" best because of the overly dramatic music and the slashing titles that rip across the screen. The blacks seem blacker (more likely the trailers haven't been touched up or preserved as well as the films themselves), the tension seems to build in just a minute or two, and you really want to see the movie.
When I was growing up in Louisville, we had a great revival movie theater, the Vogue, about a mile from the house. About once each season, the theater would show 90 minutes or so of nothing but classic trailers, so you could see the best from Hollywood and abroad. Sometimes, they would book a few of the films, such as a "Reefer Madness," for a midnight showing. Or they used it to promote an upcoming festival of, say, Ingmar Bergman films. But mostly, it was a program of previews that made you appreciate the art of selling a film in a limited amount of time. They were fun evenings and often drew a good crowd.