I just finished reading the book Long Way Round. It's by enthusiasts Ewan McGregor and Charley Boorman. Long time friends, their plans to take a ride through Scotland turned into riding around the world and making a TV show about it along the way.
Ewan and Charley rode from London to New York City - going EAST. Lots of trials and near trip-ending moments happened along the way. It's in book form and on DVD.
I can't imagine having the time to go on such a great trip as this (3.5 months on the road, with 4 months prep-time), but I would love to experience the magical moments they experienced as they rode through Prague, or outer Mongolia, where the roads just aren't roads, they're muddy bogs.
Riding well equipped BMW 1150's, they were geared up for just about every possible incident, except they didn't expect to be so radically changed when they finished. It's a good read, so check it out.
BTW - They have since completed another journey from Scotland to the tip of Africa, calling that Long Way Down.