On women I like all hair lengths and styles. Since I'm an "equal opportunity dater" (LOL) I also date African American women who lock, twist, or braid their hair or keep it natural so it's kept "short" but not really. I think closely cropped hair on women can be hot (Jenny Shimizu! HOOOOOTness) and so can long hair and other styles - it really depends on the person and the overall aesthetic they're rocking. Short hair can really accentuate a feminine face - or the opposite and make a boyish looking woman more androgynous - both can be hooooooot. I don't necessarily prefer longer hair at all, either on myself or on other women. I also like and own wigs and extensions. Variety is the spice of life!
On guys, my preferences are narrower - I generally prefer the well groomed, clean-cut look with hair that is kept short. The kind of hair that looks good with new loafers, pressed khakis, and a crisp button up shirt (that's clean, fitted, and freshly laundered). I know, I'm one note.