The answer to this question seems to change every few years. At the moment I would have to say my favorites are the Hobbit films. Although I do love The Lord of the Rings, i find the Hobbit series much more fun to watch. I read the books as a kid, but Tolkein, rest his soul, must have been getting paid by the word. He could spend two pages describing a tree on a hill!
Previous favorites would be Braveheart (I know Mel Gibson butchered the accent), The 13th warrior, many of the old kung-fu classics, and some of the Disney/Pixar films will always have a place in my heart.