Wikipedia has a very nice entry for "Serenity". (spoilers)
This is the bulk of the thematic section:
"Themes and cultural allusions"
While the film depicts the Alliance as an all-powerful, authoritarian-style regime, Whedon is careful to point out that it is not so simple as that. "The Alliance isn't some evil empire," he explains, but rather a largely benevolent bureaucratic force. The Alliance's main problem is that it seeks to govern everyone, regardless of whether they desire to belong to the central government or not. What the crew of Serenity, and specifically Mal and his lifestyle, represent is the idea that people should have the right to make their own decisions, even if those decisions are bad.
The Operative embodies the Alliance and is, as Whedon described, the "perfect product of what's wrong with the Alliance". He is someone whose motives are to achieve a good end, a "world without sin". The Operative believes so strongly in this idea that he willingly compromises his humanity in furtherance of it - as he himself admits, he would have no place in this world. In contrast, Mal is, at the movie's beginning, a man who has lost all faith. By the end of the movie, however, Mal has finally come to believe in something — individual liberty — so strongly that he becomes willing to lay down his life to preserve it. Whedon has said that the most important line in the film is Mal's contented promise to the Operative at its climax: "I'm going to show you a world without sin", as he shows him the Miranda footage. Whedon's point is that a world without sin is a world without choice, and that choice is ultimately what defines humanity.
Joss Whedon said in the DVD commentary track that the planet "Miranda" was named for Shakespeare's Miranda in The Tempest, who says in Act V, scene I: "O brave new world, / That has such people in't!" The Alliance had hoped that Miranda would be a new kind of world, filled with peaceful, happy people, and represents the "inane optimism of the Alliance".
I did not see the movie when it was, briefly, screened in Italy. Last year I managed to get hold of the "Firefly" TV series as well, and I was entranced by this whole thing. At first the references to the American Civil War (1861-65) made me suspicious, of course, as I've been a Northern supporter all my life, what with slavery in the Confederacy and all that.
And that's why I find this piece above so nicely written. The key point is indeed Mal's sentence: "I'm going to show you a world without sin". What's so powerful in Firefly/Serenity is definitely the absence of religion. That's clearly a world without gods, and people can only live their lives hoping that at the end of their journey, they might have "made a difference", a perfectly reasonable, human and normal desire.
And Mal's end-of-movie belief is something that has indeed being a beacon throughout his whole life, again, something we can all relate to, nothing mystical or "on a higher plane".
Let me admit it: I've be enamored of Western movies since I was a little kid, my first hero was "Shane" (1953), played by Alan Ladd.
I feel this can serve well as the starting point of this blog.