Hard to tell... maybe:
1) Dolph
2) Bruce Willis
3) Arnie
4) Kurt Russell
5) Clint Eastwood (I count Dirty Harry as action)
6) Sigourney Weaver (Ok, Ripley is a Sci-Fi character but with lots of action going on!)
There are a lot of others where I really don't know how to rank them. Take a look, they appear in the order of my voting history at the imdb:
Bruce Campbell (Hail to the King, Baby!)
Matthias Hues (C-movies, but great body)
Christian Bale (here's somebody on the rise... wait for Batman: Begins!)
Harrison Ford (Indiana Jones)
Sean Connery (James Bond and other characters)
Mel Gibson (Die Hard franchise, lots of others, though TPOTC freaks me out)
Jason Stratham (Lock, Stock... and The Transporter ruled... let's see what comes next)
Dwayne Johnson aka The Rock (next Arnie?)
Chow Yun Fat
Tom Cruise (frankly, I hate the guy but he tends to be in very good movies)
Jet Li
Vin Diesel (great beginning with Pitch Black, recently only crap but I'm still hoping for the best)
Jean Reno (Leon... just great)
Marc Dacascos (great fighter, mediocre movies besides Crying Freeman)
Nicholas Cage (for Face/Off, Con Air and of course a lot of great non-action movies)