Simply put: women. But without being (too) creepy, or stating the obvious features that guys tend to find sexy about women, I'll go with a few random ones that I tend to find attractive, for no apparent or rational reason:
1. ...with short, shoulder-length brunette hair
2. ...wearing striped sweaters
3. ...wearing cropped denim jackets, unbuttoned, with a tank top or short sleeved shirt, underneath
4. ...with a combination of all of the above would make me forget my own name, howl like a wolf and then trip over my own tongue like a Tex Avery cartoon.
I like little quirks. And foreign boys. That too! I'm so grateful that my boyfriend is English, I get to listen to his delicious accent all the time. He had pretty good teeth for a Brit apart from his two front teeth that overlap a bit.. super sexy.
Also.. bed head, 5 'o' clock shadow, and, oh hell, even morning breath is sexy to me.