Best Western Shootouts.

[SBRPearce]

For sheer iconic Western, I have to go with John Wayne in True Grit. Four on one, reins in his teeth, Colt in one hand, spin-cocking a Remington drop-lever carbine at a full gallop...

I once played in a Western RPG campaign in which one of the characters got to play "Horatius at the Bridge" just like that. I have never seen such a run of perfect attack rolls, and rolls to persevere after taking damage. It was the sort of episode that we game for... Good times.

[Hawkeye]

Appaloossa (an under-rated Western, in my book. I love it).

A great two-line exchange after it as well.

"That was fast."
"That's because everybody could shoot."

[joroas]

Old and forgotten: the end of Shane.

[Malamute]

Old and forgotten: the end of Shane.

Good one, Jack Palance at his sneering best. If I recall the sound of the pistols firing is really booming. A great western.

Hawkeye is spot on with Appaloossa too.

[Jim French]

I would also cast a vote for High Noon.

[DS615]

Pale Rider.

The shootout in Open Range everyone loves "borrowed" very heavily from it.  If scene for scene copies can be called borrowing.
Didn't do it justice IMO.

[Bullethead]

Start to finish: the final shootout in Open Range.  Holy crap, what excitement!  Borrowed or not, my all-time favorite!

[mjkerner]

Yup, Open Range here, too.  And though technically not a Western, the shootout in "Ride With The Devil" where the Bushwhackers are trapped in the Widow's house by Union Cavalry is probably my second favorite.