For the poll, I'm pretty much an equal mixture of Dean, Cas, and Meg.
I've got the same pop culture and musical taste, love of classic cars, tough guy attitude, and protectiveness of Dean.
I'm usually a third wheel, independent yet craving friendship, eager to please, and often torn between two different choices like Cas. Plus, a lot of things and situations he does or gets into just remind me so much of myself. And nobody laughs at my jokes, so I relate to Cas very much.
Finally, I think I'm a lot like Meg, probably my favourite (and in my opinion most severely underappreciated) character in the whole show. She didn't show up very often, but when she did, I saw so much of myself in her (minus the murdering). She's got sass coming out the wazoo, a swinging melodical speech pattern, stands for what is important to her, and wasn't all bad like everyone thought. She wants the guy that doesn't often seem to want her, and that I can definitely relate to. She's like the Scarlett O'Hara of the show, going from cruel and selfish to loving and selfless, and that makes her really special to me.
So, I'm basically 1/3 of each of them.