Regarding charging a battery pack off your usb port, what would you do when away from your pc for an extended period, e.g. on vacation, at a conference for a few days, whatever? With the flash cards that hold dozens of books, its possible to be away from the pc for literally weeks at a time and still have plenty to read. And would the bp cost more than it does now were such a system implemented? One may argue that the added cost would be saved as one didn't have to keep buying batteries. But that's a few dollars here and there over time, versus a bunch all at once, which cost is perceived differently because it must be paid out all at one time. Mary