As said, it really depends on the person's body type. Although I prefer more clothes on people because of the desensitization to flesh we have in our society.
It really depends on the person and how they look, but in my personal opinion I enjoy a man's naked torso to a woman's.
I guess it also depends on the way it's presented.
Interesting question. I tend to disagree, but only because I think both sexes look sexier WITH some clothes on. It probably doesn't make any sense, and it's not that the sight of a naked man (well, some naked men, anyway) wouldn't turn me on, but when I think about what just LOOKS hotter, I'd have to say clothes on - lingerie or a sexy dress for a woman, and either shirtless or something dressy for a guy - slacks and a shirt, uniform, etc.
I think I'm pretty visual, like a guy. I like good looking men in as few clothing as possible. We've had a very hot summer and there have been a lot of workmen around our neighborhood. *sigh* Shirtless....