That’s the random question of the day.
After Leia was captured at the beginning of New Hope and brought before Vader, she said “Vader. I should have recognized your foul stench as soon as I was brought on board.” (Really, Lucas? You’ve got to give props to Carrie Fisher for delivering that line with a straight face.)
My assumption was that she was just being insulting. However, in light of seeing how badly Anakin was burned in episode III, it struck me out of the blue today that maybe Vader really does have a distinctive odor. That would have been a really interesting aspect of the character. It puts a whole new spin on the Robot Chicken parody though.
“Oh, wait, you were flying around for two weeks trying to get a signal! Gosh, you must smell like feet wrapped in burnt bacon!”
My geek cred has been diminished! It's been pointed out that Leia's line is to Tarkin, not Vader. So much for that theory.