By far the best (I heard it's not in the film, but I haven't seen it so there's still hope):
Stood in firelight, sweltering. Bloodstain on chest like map of violent new continent. Felt cleansed. Felt dark planet turn under my feet and knew what cats know that makes them scream like babies in the night. Looked at sky through smoke thick with human fat and God was not there. The cold, suffocating dark goes on forever, and we are alone. Live our lives, lacking anything better to do. Devise reason later. Born from oblivion, bear children, hell-bound as ourselves; go into oblivion. There is nothing else. Existence is random. Has no pattern save what we imagine after staring at it too long. No meaning save what we choose to impose. This rudderless world is not shaped by vague metaphysical forces. It is not god who kills the children. Not fate who butchers them or destiny that feeds them to the dogs. It's us... Only Us
seriously guys read this once then read it again out loud by the time you get to the part about cats screaming you feel the Rorschach just ooze out of this line
quick rant for Moore fans (others can skip)
This was one thing that I couldn't quite put my finger on in the V adaptation that just f-ed with me, but this takes it from the tip of my tongue to my head, one of the problems with the flick was the lack of "only us" feel, almost every fascist in the flick is so incredibly evil that you can't see yourself and your political allies sliding very easily into their place, it essentially changes these folk (fascists existed in real life and they started out as regular folk like you) into something I don't have a fear of becoming.
Thus the phrase I was looking for was "It's not some crazy uberconfident commitee in a dark room led by a bombastic John Hurt that sentences people to the death camps or imprisons for ideology its us... only us"
end rant
sorry if that was tottally off topic or crazy I just thought of it and had to get it off my chest