Only own what you can always carry with you; know languages, know countries, know people. Let your memory be your travel bag.
I'm appreciating more and more the value of a good education, and being educated. I'm sure that will bring different ideas to everyone's minds, but to me it means being well-read and continually learning, delving into the great minds of the past and present and learning the lessons they have to share. There are plenty of intelligent people out there, but it's interesting to me that being "well-read" is always a very admired quality. Yet how many people take the time and make the true effort to be "well-read?" Maybe that's why it is so admired.