I can't say I'm particularly fussy...

I like long hair on guys, and tend to have a strong first attraction to these kind of guys - but guys I end up close with all tend to have short hair. Obviously isn't a turn-off...

As for girls... I like both, but if it's longer, I just love it if it's dark. Dark hair is a major turn-on for me in girls.

As for myself, keep it sort of mid-length. It's getting quite long just now which I like because I can plait it and the wear it wavy.