I don't know what you mean by badass, but I reckon how Legolas was able to slaughter so many at great range without wavering and pull off the biggest stunts in the films, and then 'not' say some cheesy one liner after made him look like the badass.
Otherwise if it's just about who's the strongest, then it's Gandalf.
Otherwise if it's just about who's the strongest, then it's Gandalf.