I have been thinking about this a great deal, because I am fairly new. I am a quiet, solitary (but not anti-social) person in RL. My SL life revolves around literature readings, discussion groups, and art. I am definitely more talkative in SL, but I say the sorts of things I would be thinking in RL, but less likely to say out loud.
I read in someone's profile, "in SL we wear our insides on our outsides". I liked that.
So I suppose I'm in the camp of "me, but less inhibited". And, yeah, I look better in SL - not extreme, just the way I would like to look in RL.