In high school and college I grew out my hair. By the time I cut it it was half way down my back. It was really long since I shaved the sides and back since my hair is crazy thick, plus it was the mid 90's. That was a common "skateboarder" haircut and I had a couple of friends with the same cut. A month before college graduation I cut it all off, I measured what was cut off and it almost 2 feet. I miss the looks I got when I turned around after someone though I was a chick and they got an unshaven man.
I have to agree with the idea that every guy should experiment with their hair while they can. Now I have to be all clean cut for work, but thankfully no balding yet.