Medium is THE BEST and totally worth it. I usually call that long hair, because shoulder length is too long and gross..but just as an example yesterday at a sporting event there was an average looking guy but his hair made him like a hundred guys better and my friends and I referred to him as long hair for the rest of the time. It's great when it has some wave, got that flow going on. Example hockey players, or surfers, some snowboarders (like mark mcmorris, ipod, nick goepper, occasionally shaun white) most of these guys have hot hair: http://www.tumblr.com/tagged/surfer-hair my friend says she likes long hair because it's nice to grab when making out, I just like the look, basically long hair is the way to go
I LOVE when a guy has longish, messy hair to play with, hair that falls into his eyes and covers his ears. . . not long enough to put in a pony tail though lol. I really don't find buzz cuts attractive at ALL, or bald for that matter. Regular short hair I am neutral about.
I don't have a 100% only choice but guys really do look good in one look or more. I guess I'm into a little of all of them. I picked C though since it's slightly catches my eye more than other lengths.
I am attracted to the hair length that suits him. If this makes any sense. I really don't have any preferences when it comes to hair as long as it's not greasy and it suits him. I have been attracted to guys with long hair and bald, so no preferences.