The most important element of a movie is a character. This character is made or fails at the actor who plays him or her. There are a lot of awesome characters in the history of film who just made the movie to what it became.
My favourite character of all times is Tyler Durden from Fight Club, played by Brad Pitt. His lines, the way he acts, etc. ; everything is just so.... Finished.
I also like Hans Landa from Inglorious Basterds, The Dude from The Big Lebowski, Mister Blonde from Reservoir Dogs, Vito Corleone from The Godfather,...
What is your favourite movie character?