Guys what hair color on girls do you like? And why? (if you know)?

I am asking this just out of curiosity :) I am always hearing how guys like blonds. I know everybody has some kind of appearnace preferences. But I dont understand what is so attractive about them? Im not saying that they are ugly or whatever but I just dont get it. Is that even true? Well anyway Blonde, Brunette, Ginger or Black haired? And Why?