I think I'd pick Antonio Esfandiari & Phil Laak....not for their poker knowledge, but because they're just plain nuts. If you're ever seen "I Bet You", a show they've done together where they wander around town making crazy bets all day long, you'll understand. If you haven't caught it, check Youtube. It's great. I'd looooove to have a week to spend hanging out with them. Not sure I'd survive the week, but I'd sure have fun trying.
Strictly for poker knowledge though, I'd pick Phil Gordon or maybe Dan Harrington. I loved Phil on Celebrity Poker Showdown. Even though the players were celebs, and not always that great, his commentary on different poker situations was very good. I always felt like I learned something by listening to him.