Did you read
Coldsun's review of the JE-100? From the specifications and the review, I would be hesitant to suggest the JE-100 if you want more than a book reader. You can probably forget much Web browsing - even page turning is fairly slow from what I've read in various reviews.
Maybe you're looking for a MID (Mobile Internet Device). There are many new devices on the horizon and many people asking the same questions you are asking. You might want to read Coldsun's review of
WireLession W1060 as an example of something more likely to meet your requirements.
You might want to check out the
News and Commentary section of the forums. With CES just ending, there are lots of discussions of new devices, readers, etc. It might give you an idea of what's out there and why yours is such a hard question to answer.
You might also want to check out the following links for more MIDs and UMPCs.
http://www.umpcportal.com/
http://www.pocketables.net/