Another obvious one is Cape Fear.
Memento is a particularly idiosyncratic one.
N.B.: In that story Leon has no more than a vicarious interest in revenge.
Last night I watched The Horseman (currently on Netflix Instant) which seems to fit this bill pretty well - a gruesome and compelling tale of a father avenging his daughter’s sordid death after she became involved in underground pornography. The character’s not “unstoppable” in the sense of being invulnerable - he definitely takes his lumps - but he has one mission on his mind and nothing will keep him from carrying it out if he can.
Much more subtle, no 'splosions, bloodletting, or macho men wielding weapons of destruction, but I just watched The Heiress for the umpteenth time. A most enjoyable film based on a Henry James story, Catherine, poor, naive, untalented, plain Catherine (Olivia DeHavilland) lives with her snide, insulting father who thinks little of her. She is wooed by a good-looking but penniless rake (Montgomery Cliff). Father sniffs a fortune hunter, threatens to cut her out of his will (though she will still be a wealthy woman). She arranges to elope with her suitor - until she tells him she will only be a wealthy bride, not an ultra-wealthy bride. And he never shows up to wisk her away, running off to California instead. Years later, bitter Catherine agrees to meet him when he returns. (He hasn’t made his fortune and hopes he can still hop on the gravy train.) She gives him jeweled buttons she had bought as his wedding gift years before and tells him to come back later. Off he skips, and he shows up later all happy and excited, knocks on her front door…and knocks…and knocks…and the last scene is MC outside knocking and calling, and Catherine turning out the lights and going upstairs to her room, leaving him there in a panic…I always wondered what I would do in her situation. Her heart has been hardened, but would it stay that way? … I just love this movie.
Ong Bak 2, (which has no connection to the plot of the first Ong Bak movie) ends with the Protagonist outsmarted by his revenge target, overcome by the opposition, and requests the viewer to ponder the outcome of seeking revenge.
Not sure about movies, but it often came up on the old *Kung-Fu *series.
Bad Guy:“If I don’t have a right to revenge, who does?”
Kwai-Chang Caine: “No one.”
I think nearly every movie is in some form or another uses revenge as one of its themes. If it’s not a major theme, it often drives the villain or foil. You also see it in the form of jealousy. You might be hard pressed to find a movie that doesn’t have revenge in it. The only example I can think of is Il Mare/The Lake House, which doesn’t have a villain, although the hollywood version does include jealousy.
But, if you are talking about unstoppable revenge, that’s a different story. To me, that would mean a revenge so great that it consumes and possibly destroys the hero/villain even after it is completed:
Memento
Ju-On/The Grudge
Star Wars 1-6
Jet Li’s Fearless (A really good example here, where the destruction of the hero by revenge is so complete that he can’t even stop his own murder)
Jet Li’s Hero