I really like Bruce Bethke's description of the characters in Firefly. These descriptions are attributed to his friend 'John the screenwriter':
Mal is 'Han Solo [Star Wars] with an actual backstory ... Rick Blaine [Casablanca] with a spaceship instead of a night club. He's a classic lost paladin; an embittered losing-side war vet with a junk freighter, struggling to eke out a living on the fringes of civilization and the law. But underneath his rough exterior he's still got his honour, his pride, and that sense of justice that forces him to get involved and become a big damn hero, from time to time.'
Wash is a 'classic comic-relief sidekick, who gets to have all the emotional reactions the paladin can never show.'
Zoe is a 'tough chick' who served with Mal in the war - 'she's got the whole calls-him-"sir"-even-when-she-doesn't-say-it-out-loud thing going.'
Kaylee - 'it's really nice to see a woman in the role of the engine room grease-monkey.'
Simon, the doctor - 'there's obviously some bad blood between him and Mal, so I'd have to guess he has a little black bag full of patent medicines that save the day on a regular basis and make him worth putting up with.'
River - 'Buffy' - 'the ninety-pound pixie who can toss around men three times her size when she gets mad ... [probably] the focus of the entire plot.'
Jayne - 'big and tough, none too bright, obsessed with weapons, and probably worth his weight in gold in a fight.' Is the name like 'A boy named Sue'? Or is JAYNE a reference to John WAYNE?
Book - 'the preacher with the troubled past'.
Inara - 'the hooker with a heart of gold'.
Bethke, B, ‘Cut 'Em Off at the Horsehead Nebula!', J (ed), Serenity Found: More Unauthorized essays on Joss Whedon's Firefly Universe, (Dallas, TX: Benbella Books, 2007) p176.