Neither the greatest horror movie nor the greatest action movie, but I'd say it's the most successful flick in combining the two. 2005's The Devil's Rejects is a perfect hybrid that satisfies diehard fans of both genres. Somehow it manages to make horrific scenes of torture flow in perfect harmony with exciting wild west style shootouts. Also, lets put this on record, this has my personal favorite movie ending of all time! It's action packed and exhilarating without even showing you very much of what's happening. Be sure to watch The Devil's Rejects for a unique film viewing experience that deviates from the Hollywood norm of nonstop explosions & baby-faced actors.
"The murderous, backwoods Firefly family takes to the road to escape a vengeful police force which isn't afraid of being as ruthless as their target."
What an ending! (warning: massive spoilers)