Taxonomy

As I imagine many of you can tell, I've been thinking quite a bit about how to construct narrative, story and character over the last three or four months. So I quite enjoyed this essay by Chris Braak that io9 republished over the weekend on how to understand evil characters, and providing a taxonomy of kinds of evil and how they affect the appropriate responses in the fiction in which they appear (A side note, I think Gawker Media's republishing program hasn't gotten nearly the attention that it deserves. The company may publish a lot of morally repugnant things, but this program gets promising voices out to new audiences, and increases the diversity of perspectives on their sites. I'm generally, without knowing anything about compensation agreements, a fan.). Braak writes:
Obviously, there are a lot of borderline characters.  Is it right to call a serial killer an Id Monster, or an Ego Monster?  The serial killer is fulfilling what are, in a sense, deeply-coded functions; base desires that he may not even consciously understand.  Likewise, depending on the nature of his psychosis, he may not even be capable of recognizing other human beings as human beings at all.  Is this a product of an adapted narcissistic egoism?  Or simply an undeveloped consciousness?
Michael Myers is a serial killer; I wouldn't call him an Ego-Monster.
Hitler was a raging Ego-Monster - but his sense of self was so forceful that it became the purpose of innumerable Nazis that worked for him, and thus became Superego-Monsters.
In this light, something like Moby-Dick is kind of fascinating to me.  Melville has set up Ahab, clearly a kind of Ego-Monster, up against an Id-Monster - the former is so deeply self-obsessed that he doesn't care if he kills everyone around him to get what he wants; the latter represents the most unconscionable affront imaginable to a rampant egoist - a monster that refuses to acknowledge him.
There's an extent to which this is sort of an interpret-by-numbers theory of literature that suggests some unfortunate predictability. But I think it's true that, within the limits of human psychology, there are only so many stories we can tell. Understanding why they follow familiar patterns is useful: it's not that we're unoriginal, it's just that there are certain ways the universe works. I'd be particularly interested in what folks who did the Perdido Street Station book club think of this taxonomy in particular.