Guys with long hair; yay or nay?

Well, I got red hair. I'm fairly muscular and 5'11 (i think). I normally keep my hair really short, but I was thinkin about growin it out long. I was thinking fairly long, like to the top of my back or something. But I wanted to get some feedback from girls. I'm due for a haircut, since it looks like sh*t right now, lol. I'm fine with short hair, but I thought the long hair might look kinda cool (I'm irish, so i have light skin and freckles too), but if not many girls think it's attractive, I'd rather just stick with the short hair.