My fave films, well there's lots of movies I like, but some I can watch anytime and never get tired of would be The Princess Bride, Sam Rami's Evil Dead trilogy, and Serenity.
Princess Bride because of all the great lines. The swordfight on top of the cliffs of insanity, best fight scene ever.
Evil Dead 1 &2 and Army of Darkness, because of all the cheap effects and the overacting of Bruce Campbell. If those films had any other person as their star they'd be just typical second-rate horror flicks, but Campbell elevates 'em through his fine art of being so great at pulling off the hammy bad overacting.
Serenity, well I'm a Firefly-fangirl. For those of you who are unfamiliar, think of it as a group of space pirates who won't loose sleep over salvaging anything useful or of monatary value off wrecks that have been left dead in space, but are also quick to help out the little guy. Especally if helping the little guy means they get to stick it to the large central goverment known as 'The Alliance'.
It was done so well though, I loved the scene where Mal goes to the companion home to rescue Inarra, and he has his first run-in with the Operative.
Operative: "I've come here to talk, I'm unarmed..."
Mal: "Good." *draws gun and shoots the Operative*
Operative: "I am of course wearing full body armor, I am not an idiot!"
That was great, finally someone does the smart thing in a film and shoots his enemy while their unarmed, and the enemy wasn't stupid enough to go into the confrontation without armor. I didn't need to yell about how dumb they were at the screen, because finally someone acted like most of us would act in such a situation. Just one example of how well written Joss Whedon allows his characters to be, they act like normal people in a world that's anything but.