I'm all for the whole naked sex thing, if I want to see acting I go to the picture house.
But the WeLiveTogether girls hold the crown for acting. It's all staged, but they can really make it look like they are actually cruising the streets looking for a hot girl to pick up.
I would say most of the women in porn. They are acting like they actually want have sex with and receive facials from these they would never talk to outside of the porn industry.
I think a lot of BDSM porn has some tremendous 'acting' in it, especially from the very most top dommes around.
It will be interesting to see how Sasha Grey gets on with her mainstream acting career. She wasn't bad in The Girlfriend Experience, but it wasn't much of a stretch for her. Out of her comfort zone it will be interesting to see how she gets on. I also think Stoya will turn out to be a solid non-porn actress too, for some reason.
I haven't seen anyone even come close to the standard of acting Georgina Spelvin demonstrated in her hardcore pornographic movies. Even in the midst of a passionate hardvore scene she kept full control of her body language and tuned it to the demand of her character. Maybe that's why many of her movies attempt to deal with psycho-sexual aspects of human behaviour.