The perpetual nomad being the widely popular blog, Everything Everywhere, Gary Arndt has been traveling nonstop since March 2007. His global adventures have taken through 70+ countries so far, including 23 countries in Australasia/Oceania alone, and he shows no signs of slowing down any time soon.
This is by far most useful thing I have on me. It is just behind my wallet and passport in importance.
It serves as my watch, music player, communication tool, photo album, notepad, and much more. I spend a lot of time on trains and eating – listening to podcasts and audiobooks.
One of the first things I want to do when I get back to the US is to get an iPhone so I can take advantage of the other features the iPhone offers.