There was Bronson, Dolph, and Norris; there was Seagal and Van Damme; Clint was active in the genre for a long time, and there was Mel and Kurt Russell, but IMHO for my age group there are clearly three that stand far above the rest.
Arnold.
Sly.
Bruce.
Ignore their off-screen exploits. Who’s your guy?
It was hard choice for me between Ahnold and Bruce.
But ultimately I had to go with Bruce solely for Die Hard. Which at the time was a revolution in the action movie genre. If for no other reason than he actually took a beating and kept on ticking 
Yippi-ki-yay, motherfucker.
Overall, Bruce by a mile (Die Hard, The Fifth Element, Pulp Fiction, Sin City, Twelve Monkeys, …).
Restricted to what I would call “action movies”, still Bruce but close over Arnold. Die Hard and The Fifth Element might be my two favorites ever. I do like Total Recall and the Terminators though.
Arnold wins this a runaway jet fighter made of biceps.
Stallone is a victim of the years. There was a time about 30 years ago when Stallone was a giant on top of the Genre: Four Rocky Movies, including two Academy Award nominations (best actor and writing), then First Blood, the Rambo films, Tango and Cash, Cobra, The Specialist, and a few others that were big international hits. Then the wheels fell off.
Bruce Willis is the best actor of the bunch, by a mile. He can be as good as any actor around. He’s like Harrison Ford - a great action star, but with an entirely different dimension of acting skills he can bring to bear when he needs to.
Arnold is a category of his own, though. I’m not even sure he should be rated alongside the others. He was very unique in what he brought to the genre.
Interesting results so far.
Neck and neck between Arnold and Bruce. Sly’s got a no-hitter going.
It’s definitely a tough call to make. I agree with everything Sam Stone said; I guess it’s a matter of whose style you like better.
Stallone has been very active recently, and I enjoyed Rocky Balboa, Rambo and The Expendables very very much, much more than anything else he’s done since Rocky.
Arnold is an icon; his first name alone means action (or at least it used to). He’s been responsible for unquestioned classics of the genre (Commando, Predator, The Terminator, …) and some of my other favorite movies all-time (The Running Man, Conan, …), but…
I had to vote for Bruce- his overall body of work is outstanding throughout and he’s definitely the best actor of the three. I even liked Hudson Hawk (yeah, I was that guy).
Total Recall, Terminator, Terminator 2, Preditor, Commando, The Running Man, True Lies…
It does not get better than that.
Ok, try this: Stick Arnold in every Bruce Willis action movie ever. Maybe not quite a perfect fit, but it still can work fine.
Stick Bruce in Predator, Commando, Terminator… nothing.
I know it’s not an action movie but this made me imagine Arnold playing Bruce’s part in The Sixth Sense.
Then there’s Die Hard. “Velcome to dah paarty, pahl!”
Bruce is the better actor and made the best movies but Arnold is action. Sly isn’t bad with some great movies but he’s definitely third.
You can’t put Arnie in with Bruce: Arnie was the action star of the 1980s; Bruce one of the action stars of the 90s. While Bruce has a much wider range than Arnie, Arnie has no problem taking the mickey out of himself (Junior, True Lies, etc). Also, Bruce has a serious problem with letting other actors steal the show (e.g. Rickman, Osment).
As an action hero, Bruce is forever the lieutenant to Arnie.
Willis is the best actor of the three.
Hard choice. If I was stuck on a desert island allowed only the complete works of one of the three, then I would pick Bruce, he has the better films.
But Arnies big action films are better than Bruces big action films, and because this is about mindless action films, then I have to vote for Arnie. QED bitch.
DIE HARD is a great movie; THE FIFTH ELEMENT Is a great action movie. But only The Arnold has a definite article.
I agree. People sometimes forget how huge Stallone was in the early '80s when he was riding on two successful franchises. And he was able to coast on that success for a long time, earning eight-figure paydays all the way through the 90s. But **The Expendables ** was was his first bonafide hit since 1993’s Cliffhanger and his first $100 million domestic grosser since 1985’s Rocky IV (unless one counts the animated film Antz, for which he did voiceover work). Other than that, if you look at his career over the past 20 years or so, it’s basically been one flop after another - Judge Dredd, Stop or My Mom Will Shoot, Oscar, Get Carter, etc.
Arnold might have helped himself in this comparison by switching careers instead of turning out random True Lies (or whatever) sequels.