We saw Watchmen today, and I've gotta say, I think it lives up to the hype. The original comics are credited with establishing the medium as genuine literature, and were a precursor for all of the dark and scary comic-come-movie things we see out there.
I've not read the comic, only the press that talks about it, so I can't say how faithful it was (and I'm not sure I should care, but I did order the book). What I did see was a lot of powerful themes in the movie about the value of life, namely our disrespect for it, and the failure of our leaders and "super heroes" to execute on the things we hope for. Written during the Reagan era and the cold war, I can see where the motivation comes from. More than anything, to me at least, it asks of the ends justify the means when hard decisions must be made.
Visually, the movie is pretty stunning. It doesn't go the route of "comic realism" that Sin City went, and actually draws a believable, if alternate, reality. It isn't too stylized for the sake of being stylized, but I wonder if some of the momentary slow motion moments were there to pay homage to the comic. Like the one scene from the trailer, where Laurie (the female lead) turns and that beautiful, long straight hair with the bangs turns and moves as she dodges a fireball. (As an aside, that hair moves in excellent ways throughout the movie.) It's just little details and textures all over the place that make it pop.
There are some parts that are exceptionally violent too, almost to the point of distraction. I don't know if that was to keep it true to the comic, but sometimes not showing it would be better.
Overall, I really liked it. I wasn't sure what to expect. But I think it's important to note that there probably would be no Batman movies had it not been for the comic Watchmen.