Good Question lots of good answers I think I'd talk to Edgar Allen Poe, Ron "PigPen" McKernan, and Hunter S. Thompson. I think I'd also like to talk to Elia Kazaan he made great movies but why sell out your comrades? I'd also like to talk to Chaplin and just about everyone that everyone else mentioned.
I read the first series of Necroscope books in the early 90's and just recently have been rediscovering the series. I've always wondered why no one had optioned these books for a movie(s) because they were always my favorite of any Vampire books and having gone to film school i got tired of everyones "original lesbian vampire ideas" this place rocks.