I'd use it for general relaxation, gaming, and obviously, sex. prefferaby, combo the sex with the gaming.
I'd re-create some of my favorite RPG worlds, mostly fantasy and Science Fiction. It would be the near-perfect form of non-pen-and-paper D&D. Larping, but not...lame.
Zombie Apocalypse scenarios would be tremendous fun as well.
Sex. Definitely. I'm thinking thick dark hair, medium height, big hips, big eyes, round face. As intelligent as the AI can manage. Generic pale skin/red hair/green eyes would also be acceptable.