Firefly TV Show / Serenity film: Few Questions

[JJ]

Now, I'm a fan of a lot of things sci-fi, and I had never heard about either the show or the movie during their runs on their respective screens, but seeing that both are out on Blu-ray has piqued my interest! Thus, I had a few questions to ask.

I don't like to generalize, but if you could describe Serenity, what would it be like? In vague terms, i.e., "It's a little bit of _______ (other movie name) with some _________ and a little ________." Don't ruin too much for me,

Should I watch the TV series first before the movie itself? Is it necessary? Thanks, chaps, this is looking like a great blind buy to add to my collection, all the moreso after reading the sparkling technical reviews.

EDIT: And lo and behold, owa bumps up the Serenity thread as I write this. Time to go read it.