Count of Monte Cristo Ben Hur (Although it wasn't pure revenge film) Payback (Loved that film) Law Abiding Citizen (I was rooting for the bad guy)
Certainly not the best, but maybe the most under-rated and the first that came to mind for me is the Kevin Costner/Tony Scott film, aptly named "Revenge". It got lambasted by critics and made zero money when it came out, but I love it. It's cheesy, and over-dramatic, and schmaltzy, and pulpy, but somehow great. Anthony Quinn as the Mexican drug lord with the young hot wife was LOL, but also somehow fucking great.
Law Abiding Citizen is fun to watch one time. But the more you watch it, you more you realize, it's one of the dumbest movies ever.
I'm usually not big on subtitles, but I Saw The Devil is one of the best revenge flicks I've ever seen.
When I was growing up the Mexican western "All For Nothing" was the best revenge film I had seen. It was the story of two brothers searching for a posse of criminals that murdered their parents and raped and killed their little sister and brother. It is very satisfying every time they catch one of them and torture them before killing them. Their thirst for revenge makes them cross the desert on foot with no food or enough water. All that kept them going was their quest to get all the killers. Had a sad ending, though. Another revenge favorite is Bruce Lee's 'Fist of Fury' aka 'The Chinese Connection'.
You guys ever see "High Plains Drifter"? Gotta be the weirdest of all of Clint's Westerns. Ghost of Clint gets revenge on an entire town in peril. Kills the men off, or gets them to kill each other off, sleeps with the women, and rapes the ones who don't want to sleep with him, until they decide they actually like it and come back for more. Fucking strange ass movie.