i agree that culture is one of the many reasons to travel but I know I'm not much use if I've been traveling and didn't get to sleep during the long-haul flight. That might all be changing now that Air New Zealand is bringing out a new economy cabin, complete with seats that you can sleep on. It's been nicknamed "cuddle class" and I wrote about it here (if I'm allowed to post my own website, apologies if that's not allowed).
http://www.examiner.com/x-29076-SF-World-Travel-Examiner~y2010m1d26...