I travelled fairly light (for me, anyway) to Brazil, but one thing I was keen to take along was my iPhone. It turned out to be a very useful travel companion for entertainment (music, TV shows and books via Stanza) as well as a stopwatch, alarm^1^, calculator, currency converter and various other useful widgets. We had no internet or mobile phone coverage at the site, but the connectivity was very useful during the interminable travelling. I found that with Airplane mode on, the battery life was great. I also took a Freeloader with me, which was brilliant for recharging on the go. The power supply at the place we stayed was not the most reliable, but there was certainly plenty of sun, so the solar panels of the Freeloader charged up its internal battery quickly. I could then recharge the iPhone (and my camera) up at my leisure. It works well in the UK too, though it takes longer to fully charge, but you can also charge it via USB from a laptop.
I lugged a paperback copy of War and Peace to Brazil (875g!), but if I had been a bit more alert, I would have noticed that it is available on Stanza, so I could have taken a weightless literary tome with me on my iPhone.
^1^ I recommend 'Piano Riff' as an alarm tone. It brings a bluesy, dramatic start to the day, and you wake up composing "I woke up this morning [da-DA da-DUN]..." blues songs. It also goes well with howler monkeys. ↑