I think that redemption and fate/free will are the most crucial themes of Lost.

I can't really pick any one of these. Each one of them played huge role in the LOST theme that's what makes the show unique. :D

I love all the above bcoz they`re LOST!♥

I would say Personal Redemption/Human Behavior, but that's more my personal idea of what the show's main theme is because it's what I'm most interested in. The show itself I'd have to say this, or Science vs. Faith

I'd say all really. But if we're going for the main theme, it's definitely this... it's always been about fate and destiny for every aspect of the show.

When I first started watching it wouldn't have been this at all but now especially during this season I'd say it's definitely this.

Hahaha, they're all just trying to beat fate and get back their free will, because by the looks of it, none of the Losties are a big fan of their fate :P

Each of them is a huge part of the show. I pick free will vs. fate because they bring it up in about every episode. Especially lately.

To me right now, it's pretty obvious it's free will/fate!

totally think so...

but latley im seeing more of the good vs evil aspect comming into play.

For sure.