There's probably a thread like this somewhere, but I fail at the search feature.
This can be a cartoon character, sitcom, action whatever. I guess it can even include comics and video games. Probably should just exclude anime, since there's a ton of those types of threads in the manga section.
For me, it's a three way tie.
John Abbruzi from Prison Break is the shit. Everytime he says something all I think is "What a badass." Sure the mafia thing has been done, but this guy is just awesome. I haven't finished watching PB, but I'm sure he gets better (yeah, I know he dies at some point.) The fact that he's the spitting image of Crocodile (minus the scar) puts his badassery score above the rest.
Next is Sawyer from Lost. Sure, he's the "Sasuke" of Lost, but he's another bad ass character. He's incredibly clever, he's got street smarts, and he's not that stupid. Plus his huge bag of nicknames doesn't stop me from laughing. The episode with Hurley fixing the car made me love Sawyer's personality, especially when he called Charlie "Jiminy Cricket". I lol'd.
Last would be Tyler Durden, from Fight Club. The movie itself was freaking insane, especially after you re-watch it. But Tyler was the shit. His clothing makes him look even cooler, and when he re-appears at the end of the movie with the fur coat it made me think "He looks like Doflamingo." The fact that the character is a literal mind fuck makes him one bad ass mofo. Even if he wasn't real.