Just finished reading the graphic novel. I was very impressed how close the costumes in the movie were to the comic book. And Master Shake, I would agree with you that the ending of the movie was a bit better then the comic book. I don't like the person they cast for Ozymandias but other than that I was impressed that all the key dialogue was there. I would have loved to see some of the things in the comic book depicted the same way in the movie (Rorschach's capture of the pedophile, the rooftop rescue, the assassination attempt on Ozymandias). They made up for this with the perfect casting for Nite Owl and Rorchach.
I would definitely go see this again in the theater. This is quite possibly the best comic book adaption to a movie, and I will probably be watching the direct to DVD release of the subplot that was completely missing from the movie.
I got mind control while I'm here
You goin' hate me when I'm gone
Ain't no blood clot and no fear
I got hope inside of my bones