I know most people on here probably did not see it, but John Cena's character in The Marine... he was pretty badass and of course having Robert Patrick play a slick, take no nonense bad guy also helped, and he was badass in his own right. I have to agree with most everybody's lists. They are all really good.
in no particular order
Eric Banas' character in Black Hawk Down
"Good"/Eastwood in The Good, the bad, and the ugly..and in fistful of dollars etc
Lex Luthor (one of the most badass characters in general (actually in the movies he's kinda wack compared to the comics, cartoons, and tv shows)
Snake Pliskin
Neo-Matrix
Darth Vader in Star Wars
Radio Rahim in Do the Right Thing (not action movie but w/e)
Christian Bale in Equilibrium
Tom Cruise/the hitman in Collateral
Indiana Jones
but just as a sidenote Jack Bauer could kick all those characters asses if he was in a movie