I noticed early in the thread that people were talking about battery life. I found that my phone would expire far too early if I was on a longish train journey so I bought an external battery pack for charging on the go. The one I have has enough juice to charge my phone a few times over, or my ipad a couple of times, or an ereader once or twice (being as how the battery lasts longer, no need for more). Its been a boon. Its an earlier model of this one
http://www.mokiinternational.com/Pro...Bank-7800.html