I’ve been thinking about Scott’s post in which he talks about attitudes towards character development, but I think that he may be conflating two different things: approaches to playing the character, and the type of character one plays. I think they’re related, but are not the same thing at all.
Scott’s List was:
1) hero fantasies
2) ditzes
3) competency
4) real life
and although he didn’t number it
5) different as possible from oneself
Heroes, Ditzes (or Eccentrics, as Rachel prefers) are, I think, types of characters, Oneself and Competency are approaches to playing a character, and Different as possible from Oneself is a motivation for playing a type of character.
For instance, one could easily imagine both playing a Hero because it was different from oneself and attempting to play the Hero in a maximally competent fashion.
Actually, the topic of categorizing styles of play, motives for playing, and even types of characters has been chewed over at great length in places like the rec.arts.gaming.frp.advocacy newsgroup and elsewhere.
Tales of the Rambling Bumblers 
I think I play characters that are different
from me in one or two ways, and similar in
all the others (except as follow from the
differences.) It's like an experiment, where
you want to control for other variables to
see the influence of one. Thus, playing
Evil characters means that I'm experimenting
with bizarre moralities. Any other experiment
will usually lead to playing a Good character,
out of self-delusion.
You play characters that are different from eachother? Huh.
Just kidding