I use a USB book light on occasion when reading, mainly because I had the light already and the port is a good anchor point. I found that while flash memory drives work with the eGDe, USB-powered hard drives don't (probably draw too much power). Personally I would really like a GPS attachment of some kind to work with the eDGe. Yeah it's is a little big for navigation use, but it would be handy to have since so many Android apps use GPS.