[martinglake]

Sony Prs-T1 - for pencil style that can be erased after closing and reopening on PDF or ebook

Do not root it or upgrade the firmware.

I did so and lost my onscreen keyboard and wifi and there was no benifit to the root - the only thing I wanted was the android calendar and this didn't work.
Luckily I use neither and just need this as you do to annotate PDFs and ebooks.

There is no truely mobile device on the market other than the ebook and this is why it will see a resurgence in growth over the next ten years as a administrative field administration device and digital signage.
Mobile phones are tied to their charging docks. The definition for netbook mobility is moving from one charge point to the next...unless you have the place of mind to continually remove your battery or unplug, or can afford a new battery every month after you inevitably leave it plugged in over night ... So there is no alternative....With moder technology it is not a question of adding features but making the most basic features work consistently for a day without battery concerns. Only Eink can do this. And to be fair it could do it in 2005 but the industry is busy milking the fad cow first. Eventually there will only be the functionality market left.

Note the jetbook pro (which I haven't tested) and the sony 13 inch device coming out later this year. Sony and samsung (each with android base) are going to be your best bet. Unfortunatley the T1 and T2 have poor file transfer functionality so lets hope the ability to share the pdfs from one ereader to other devices becomes email based rather than some fadish facebook antifunctionality. For now it's a wire....luckily having and android base - PC connection is plug and play.