The biggest need as I see it, before any other consideration, is to make the book bigger or resizeable. Even increasing the font, I will not use it otherwise, as only a few lines appear on an individual page.

I would love this if the book could expand (and with it the font size). It would be a pleasure to read then. FYI I am using Windows 7.

More minor considerations as others have mentioned...perhaps a variety of desktop surfaces (different woods). 3D would be nice, not necessary, but would increase desireability. Perhaps a page or chaper guide that could be opened to the left of the screen, and in Adobe Reader or Microsoft Word Document Map view.