I had an idea for the ghosts, tell me what you think. Say the Ghosts each had a different voice, or say you could choose from list of twenty or so voices for your Ghost, each with its own dialogue and personality. With multiple Ghosts out at once, they could talk to one another, or even bring up past experiences. From what I could gather, the Ghost is similar to an AI (lest I be mistaken) and Bungie wants Destiny to be all about you and personalizing your person, this would add to the effect, each player having a choice for their Ghost. Also say the Ghost could recognize players that are friends.