Amazon.Com -- Mack daddy of all DVD and Book sites.
Celluloid Dinosaurs -- Supposedly every dinosaur movie ever made.
Fangoria Magazine -- All things in film that are grotesque.
IMDB -- The Internet Movie Data Base. It has a billion movie listings. More or less.
The Missing Link -- Very cool Classic Horror Movie site. Has a lot of rare and obscure info.
Saturn Awards -- Home of the Saturn Awards for scifi, fantasy and horror.
Scifi-Movies.Com -- In English and French. Very slick with a couple thousand listings.
Sixtiescity -- 1960's Sci Fi Films. Pretty good with several hundred listings.