Ok, I'm one of those guys with a pony tail not because I like it, but because otherwise my hair would get in my face constantly , and that sucks. Also I depends very much on the individual , most guys who have long hair usually are metal fans and it fits.
Definitely depends on the man and the quality of their hair. Thin, straight, greasy? No way in hell. Thick, wavy, or curly? There we go. If he looks like a viking, knight or a pirate, he's doing it right. If he looks like a computer programmer or art professor, he's likely doing it wrong.
Depends.... but I normally don't care unless it's down right horrible and even so I don't judge people by hair. Though I have heard/believed that it shows personality at times.... It really just depends.