Just keep it clean and healthy. Greasy hair is never hot, and when it looks dry, frizzy, and split as hay, that's not hot either.
My only flame is that at my age, a dude with something like purple or blue hair would turn me off. Natural colors are always best. The most important thing (either than cleanliness) is making sure that it suits you. Make sure it's compatible with your personality, your style and facial shape. Hair says a lot about a person. Put some thought into it. Make the right decision for you.
My favorite, or at least the one that always catches my eye, is medium. Long hair usually looks unkept and greasy. Buzzed hair is ok, but it's not as attractive in my opinion. I love hair that is "shaggy" I guess. The first and last pictures on this page are definite eye catchers for me link
I love medium length hair, especially if its curly! I think it gives a guy character and frames their face better than a buzz cut, but every guy is different so some guys look great with buzzed hair some look great with shaggy longer hair. Moms always want their sons to have short hair I'm not sure why, I think they feel it makes them look more polished up or something. Ask a friend that's a girl and see what they think.
Medium is sexy! I think most people like medium to short all the way. I've never been attracted to long hair...but really it depends on the style they are and if they can pull it off. link personally I love his hair! And him *giggles uncontrollably thinking about him*
But yeah personally medium to short..and clean...and slightly curly, gives a bit of personality to the guy ya know?
:D Yay! (To the Update: Wow! Thanks for all the answers! Yeah, I'm sticking to medium hair.)
i like short to medium
Personally I like about medium length hair but it depends on the hair type. I love my boyfriends hair. It is medium length and curly at the ends. He fixes it where it flips out on the ends too which looks rly awesome. I also love my exboyfriends hair. It is medium and straight.