Lotta good ones.
Someone mentioned Unforgiven. I like it when Gene Hackman says something like: "You wouldn't shoot an unarmed man, would you?" and Clint says: "You should have thought of that before you decorated your bar with my friend."
I also like the Clint scene in Heartbreak Hill, when he makes short work of beating down the bodybuilder who comes in to the chant of "Swede, Swede, Swede..." The "Did I Fire Five shots..." in Dirty Harry is cliched now, but is still movie magic.
Who could forget Rocky running up the stairs of the art museum or the landing on the beach in Saving Private Ryan? Not really my favorite, but unforgettable...
I also love the scene in Planes, Trains, and Automobiles where Steve Martin is stranded out on the Tarmac, makes it back to the rental car counter and unleashes a tryrade of obscentities.
How about in Good Will Hunting where Matt Damon talks about his alcoholic father saying he could pick the belt or wrench to be beat with and saying: "I'll take the wrench."
Or, when Arnold says: "Come with me if you want to live" in Terminator 2.
Or, just about any scene in 300.