It's not which gun-play scene was the coolest. It was about which ones became cinematic masterpieces, a moment where you the viewer are pulled into the reality being shown on film and you feel every shot, without the need for the blaring 3 gagillion watt sound system in the theatre that is waaaay too loud (went to see a movie one night and could hear every bit of the Star Wars re-release in the room next door).
I haven't seen many of those films, but I know from what I've heard that they are spectacular. The first time I saw Leone's "The Good, the Bad, and the Ugly", I was awestruck by the ending, and upon reflection, the entire cinematography of the movie. It falls into the realm of Epic, along with Apocolypse Now, The Great Escape, and even 2001. What some people won't do to make a buck.