Johnny Cash, Hunter S. Thompson, and Trent Reznor. Johnny Cash was allegedly good friends with most Presidents up until his death, and he just seems like the kind of bloke I'd want to sit down at the pub with and pick his brain. Reznor is a more a "Let's go get completely wasted and muck around with drum-machine programs when we're done with this meal". I think it'd be nice to meet someone who's generally had a positive influence on your life. On that note, I'm also adding Adam Duritz to the list. As for Thompson, well... Why wouldn't you? Other than the fact that he'd probably be several days late. Or early.