Definately Zero.
I don't know why, but Kaname just gives me the goosebumps and freaks me out, especially everytime when I see how he acts towards Yuki. I don't know, maybe becasue he's too much of a gentleman?

I don't hate him, but just don't like him all that much...
Whereas I really just adore Zero. He's so cool! I just love characters like him. He may seems cold at first, but he's just really caring deep inside and wants to protect Yuki so badly. (i heard rumors that he was about to shoot her or something, but since i haven't seen or know the reason for that, i still say that he cares for her)
so, yeah, ZERO!^^