I'd say the Hive, but the implants might make keeping a secret difficult.
Hellhound: I'd love to try an actual Cyberpunk game and I can think of no one better.
Nightfall: I love the Scarred Lands and would love to play rather than DM, and he is the expert on the subject.
Jennifer Connely: Just because I want to be in the same room with her.
Edit: Can't leave out these people
KitanaVorr; Having read some of her PbP games I gotta say I'm impressed. I fear her tyranny just a bit,

, but it would be good for me.
Mark: I like what I've seen of his work, and he's an all around great guy.
I would really like to play with any of my Hivemates, EternalKnight, Maldur, Ashwyn, Tallarn, Randomling, Crothian (for his superior game collection

) and too many othes to be named.