I would also add the end fight of the movie Serenity where Summer Glau takes on the Reavers.
Others that come to mind, the Warriors vs. the Baseball Furies in the Warriors movie. Perhaps that’s because as a Red Sox fan I liked watching Yankees fans get beat up, ha ha ha. And Ajax was always one of my favorite Greek heros, as far as I’m concerned the first Objectivist.
For comedy, the end fight scene from Slap Shot.
My favorite scene where River gets into a killing mood is in the series ("War Stories" episode) , when she takes a quick glance and then shoots 3 men with her eyes closed.
I'll have to check out some of the movies you guys are mentioning - I haven't seen many of them.