Yeah, I still think this is a nice, legitimate topic for discussion. :D
Post more in it, please? :(
Just so it doesn't look like I'm bumping for the sake of bumping, I'll add this:
I think guys can do just as much with long hair as girls.
For example, dreadlocks. The act of not combing or cutting the hair at all to the point where it becomes tough and basically unmanageable. Some people have their hair like this. Knuckles the Echidna has dreads, and I'd say they look awesome on him:
Cornrows: Some people don't know you need considerably long hair for cornrows (if you want "tails" at the end of them, at least), for it to be braided tightly in lines near the scalp. I know there's at least one person who tried to "simulate" cornrows by shaving lines into their head, because their hair was not long enough.
Some can go really crazy with their hair and just let it be, as it is after waking up in the morning, such as Ludwig von Koopa:
His hair is just marvelous, and it's quite funny that he has a full head of long hair while his only sister does not.
So, ja, guys can do lots more with longer hair than shorter hair.