I thought I would add one of the reasons a user replaceable battery is a deal breaker for me. I frequently am out of reach of power for days and sometimes back to back 2-3 week trips with little time to regroup. So, my devices need not only long battery life but the ability to swap out the battery. I carry at least two solar trickle chargers to extend the 5-10 batteries I carry for those two devices.
One of the uses of an ereader would be on pack trips when working on a project. I stopped bringing pbooks years ago and have used a PDA for ages and still do carry two of them. An ereader would be a much better device to carry and reduce the weight of what gets stuffed into the pack. It would allow me to add small laptop over the PDA and it's accessories (which I use for work but could be better done on a lightweight laptop/netbook/tablet.)
This is also a reason a plastic display is what I will hold out for unless something very inexpensive and with the other features I really know I need comes along. the Txtr was a very promising device, until the info about the battery came along. An ereader, plastic/flexible display and 1-2 extra batteries and I would be golden for entertainment for a couple months if I needed it, even w/o the solar charger. Will likely never get rid of the pocket pc type device as I keep a database and notes of what I am doing along with location details as well as a trip diary on it. I doubt there will be an ereader device that can handle this for some time yet.
I'll admit I go on fewer of these trips every year, but still have four with possibly a 5th & 6th, over this coming summer and fall. Sleeping on the ground is getting harder to get motivated for every year.
Still the pictures are worth the effort.