It seems like the famous Augustine quote about travel wasn't actually from him:

“The world is a book and those who do not travel read only one page.”

But it is a great sentiment, isn't it?  Traveling enriches a person's life; people that don't travel miss out on a variety of experiences, but the biggest thing they miss is a changed perspective on their own reality.  These two quotes, one from Henry Miller and the other from Mark Twain capture that spirit:

One's destination is never a place, but always a new way of seeing things. (Henry Miller)

Travel is fatal to prejudice, bigotry, and narrow-mindedness. (Mark Twain)

Susan Heller, however, may have one of the best quotes about travel as she lays out advice for packing a suitcase:

When preparing to travel, lay out all your clothes and all your money.  Then take half the clothes and twice the money." 

Words to travel by.