The voice of Cortana brings tingles to the loins of any gamer who's picked up a controller over the past 5 years, and that sexy sci-fi haircut that she keeps changing just in time to keep ahead of the fashion makes her just that little bit freaky. She's domineering enough that you respect her, but she'd never boss you around and she's more than happy to run a game of Halo 1 co-op with you. You need her as much as she needs you and the relationship would probably work out just fine. Sounds perfect, right? Wrong. She's a 30cm hologram. Sex with her would be as exciting as Air Guitar is to Richie Sambora. Next.