When you break a sweat you just feel great. You've got your endorphins going. You feel better. You look better. And if you aren't able to get a workout in, try to find a steam room somewhere. You just look and feel so much better after a sweat.
I think the sexiest thing about a man is that he's confident. Sure, sometimes you meet someone and you see his appearance first, but then you get to know him, and he looks completely different to you.