I can definitely see the resemblance, Arwen, short hair aside. (Unless you've recently cut your hair that short, too.)
I dunno, Emmy - it's a thought provoking question to be sure. But it's a difficult one. I'll use GLR for an example. GLR says that she thinks that face-painting makes people think of her, but that's barely the case for me. Crawdads, rolling green hills, King Charles spaniels, and brown couches with too many pillows make me think of her. CatHerder's another example: many will think of him when they see lots of cats or stained glass, but I think of him when I see a rare Jetta GLI or if someone mentions a whorehouse (long story).
What makes me...me? It depends on who you ask. To the people in my church, my voice and the 5-string electric bass that I play are what define me. To some of my students, it might have been my hair or my brony-ness that defined me. To many of the musicians in town, they only know me as "the bass clarinet specialist who teaches on the east side." To the people at the wing joint, I'm either the karaoke guy or the celibate flirt. I can try to define who I am to me, but in the end...it's always what others see that ends up defining us. I could TELL everyone that I secretly rescue puppies, that I'm working on a cure for AIDS in my spare time, that I'm on the verge of solving the famine issues in north Africa, and that these are the things that make me the quintessential Shour...but in the end, people are going to define me by their own eyes, no matter what I say.