In porn? In terms of energy, looks, body etc Annette Schwarz comes to mind first then Nina Hartley. I'm sure if I thought about it though I could probably name half of the girls ever in the adult industry lol.
In porn, I think Rachel Starr is one of the most attractive stars out there, but I hesitate to give her a perfect 10 because of her fake tits, despite the fact that they look great on her (I just prefer naturals...personal preference).