I enjoyed reading on almost all of my ebook devices, but have to say I really liked the backlighting of the Rocket Ebook series - both black & white and color versions. I like to read late at night, and I'd prefer to turn off the lamp at some point.
For me the best ebook readers are the ones that have such a pleasant interface that I simply lose myself in the book. I, for one, like to forget I'm using a device after awhile, and be left to dwell on the content therein.
The perfect ebook reader would combine the backlight of the Rocket ebooks, the great page-turning bar and hardware buttons of the iLiad, and the size/fit/feel of the Sony Reader. Of course e-ink is awsome in bright light - and both the iLiad and Reader have great displays.
From the original Rocket ebook through the Treo's, pocket PC's, Libre and now the iLiad and Reader; I've tried them all and ultimately think that what really makes the reader is a great book... (Pun intended...) So the fewer hoops we collectively need to jump through, the better our experience.
Just my 2 cents...
Larry Z.