Having just spent over a month travelling, and having done a similar stint three years ago, two pieces of technology have changed the experience quite fundamentally. Frankly, if you’re planning a long trip anywhere, these two tools are indispensible:
Reading books is cool, not having to lug them around with you is nice too, but that pales compared to the Kindle 3G’s killer feature: Completely free internet access almost anywhere in the world. Granted, the browser is slow, but for travelling being able to access the internet anywhere is amazing. You can read Wikipedia articles (which are treated very nicely by the Kindle’s built-in Instapaper-like Article Mode) for historical sites while you’re there. You can access the wealth of eating & drinking recommendations (and not just the one’s in the guide book!) , and you can keep in touch with emails. You never need to worry about having wifi, or finding an internet cafe, you just turn it on and it works.
Google Maps (Android)
Why Android specifically? Offline maps. This launched while I was in Istanbul, and it was a Godsend. Suddenly, I could always whip out my phone, and see in an instant where I was, as GPS works without internet access. No more getting lost, no more worrying about keeping track of where I was and how to get back. The maps it downloads work at all zoom levels, and include points of interest, bars and cafes (just the points on the map, not the actual Places pages for them). You can download maps anywhere, so you can get a map for the city you’re going to next, and not have to worry about how to get to the hostel.