This falls under personal preference but its not the only factor.
I like what looks good on the girl. Its different for each girl, what works for one might not look very good on another girl.
like the short hair long hair debate. Its not a matter of what looks better in general short or long hair, its about what looks good on that particular girl.
Some look better with long hair but weird with short hair, some look better with short hair but can't pull of long hair, some can pull off really short hair like Hale Berry but dont pull off the other two well, or there's girls who look good regardless or they look equally as good either way.
And hair styles, find one thats a great fit for you. Be sure it complements your features and face. And by all means pick one you feel comfortable with, and feel really confident with. But the very basic theme it has to follow, is it needs to be a good match for you. A hairstyle could look really cute on one girl and not as much on the other girl. Meanwhile the other girl's hairstyle's great on her but would look kind of off on the first girl.
And yes personal preference plays parts in this too. And also factor in guys dont notice and appreciate girls hair like girls do with other girls. What we usually notice is the girls face, yes we have hair styles we like and its attractive when a girl does her hair a certain way that makes her more attractive, but its not emphasized like how i guess girls think about their hair. Also it could have a negative effect if it didn't suite your face.
Your hair isn't usually on our top priorities , girls themselves put more emphasis on it probably because of fashion magazines promoting and emphasizing it as you were growing up. Not to say guys like it if you didn't take care of your hair at all. But its not emphasized with us as you think. :)