This is a few years late, but it explains trailer's lack-of-a narrator in recent years.
http://en.wikipedia.org/wiki/Don_LaFontaine (http://en.wikipedia.org/wiki/Don_LaFontaine)
(Hopefully, there's not already a topic on this.)
From almost 5 years ago:
DON LAFONTAINE, "VOICE OF THE MOVIE TRAILERS" DIES AT 68
http://www.badmovies.org/forum/index.php/topic,120852.0.html (http://www.badmovies.org/forum/index.php/topic,120852.0.html)