I love almost everyone from Firefly. But if I had to pick just one, I would use completely arbitrary guidelines to eliminate most of the crew of Serenity and come out with Mr. Jayne Cobb himself.
Wash would also be acceptable, but Cate has already claimed him.
Jayne, the Hero of Canton. What is there to say about him? He always says what he thinks. Much of the time he doesn't think something appropriate, but one has to admire his ability to say what everyone is thinking sometimes.
He also impresses the audience with his fighting, his weapons, and his bartering skills.
It is my very favorite gun. . . . I call it Vera.
It should be noted that Jayne has a theme song. Do you know who does not have a theme song? Most people in the world. Jayne is Robin Hood in some parts of the galaxy, people. They write ballads about him.
He has a loving family, too, which I think any person would be happy to have. His mother knits. If we go only on those two facts, Jayne's family is identical to mine.
Now, do you see what I'm saying?
Images via Firefly Wiki.