1) Remove the Ebook-store icon from menu, make it prominent within the Library app itself. (Its easy to bump this icon / and the menu bar when typing - I like the idea of a hideable menu bar).
2) ICONS for the library. It should be possible to add an icon for a pdf document. It should be possible to take a picture of a particular page to use (then for PDFs and Google books, a person could say that the title page image should be the thumbnail for the Ebook). It'd be beautiful to see a library of book covers, and flip through the books this way.
3) Be able to choose a default starting tag for the library (rather than the whole library) - because of how long it takes to load the library app. I have nearly 500 ebooks (PDFs mostly), since I use this to hold my research articles. Finding ways to speed up this app is a must!

-Matt