OK, so my initial thoughts on the film have been tempered over time, mostly due to reflecting on the reactions of other people, some of whom have read the original story and some who have not.
I think I may revise my initial recommendation to suggest that you should see the movie only after having read the book (even though I know most people won’t bother). I now realize that I may have been taking too much for granted in basing my appreciation of the story on things that I was aware of by way of familiarity with the source material. It is now apparent to me that someone without that prior knowledge would necessarily have a very different experience, since they can only digest the parts that the movie version presents.
Here are two notable highlights that I encourage everyone to read that give a good perspective that may be missed in standalone movie viewings:
 Gareth explores how the missing pieces in the movie (at least that’s part of the reason) can lead you to miss the point of the message on “heroic violence”. I mentioned a bit about changes I had heard about in this regard in my comment on Alex’s blog, but I forgot to come back and touch on that in my review. In short, I agree that you definitely are not meant to view characters like Rorshach as “good guys”; rather you’re supposed to be disgusted by the lengths that they go to in pursuit of their cause, or at least be upset with yourself if you do find yourself rooting for them.
While I actually think the movie may have dulled this to some degree by making Rorshach (and the Comedian, to some extent) a bit more palatable by way of amping up the brutality in some of the other characters which were not portrayed that way in the book (namely Dan and the Silk Spectre), I believe that further reflection must challenge us to question why (as a society) we don’t seem to be repulsed by this sort of thing. On the contrary, we root it on in most cases, as far as entertainment goes. Even when the author of the story is intending to push you over that edge and make you question yourself and who you’re attached to in the story (and why), it doesn’t seem to come across too easily. It’s easy to blame this part on the failing of the movie to carry forward that aspect of the story as faithfully as it should have, but I don’t think it’s quite that simple.
 Tim explores this aspect of it very well in his post on the nature of vigilantism. An excerpt:
Rorschach is a parody of a type – a type that remains resolutely resistant to parody. No matter how far the creators go in order to paint the vigilante in an unflattering, belittling, comical light, as long as the essential motivation of the urban vigilante remain untouched, the appeal can’t be diminished. Rorschach is dirty, destitute, delusional, traumatized and dumb, and yet we still want to identify with him. We still want – we still desperately need the freedom to condone his actions, despite their reprehensible nature.
Anyway, sorry that this post was a bit more of a downer than the first one. Don’t get me wrong – I still enjoyed the movie a lot; I’m just not quite sure at this point what I would think of it if I didn’t have the advantage of having experienced a lot of back-story aspects that flush out the story and intended subtle messages so much more fully.