Books in Brazil, and the paper used for them, are tax exempt. E-books got the immunity too, they were never charged taxes since their appearing. What we pay when we buy e-books outside is IOF (Imposto obre Operações Financeiras, tax on financial operations), which does not occur on the acquisition of the e-book (which would be unconstitucional), but on the fact that money went from Brazil to some other country. It was 3% last year, but to disencourage Brazilians to spend outside, by a decree it is today nearly 7%.
That bill proposal of e-reader tax cut, as comparing them to books, was part of the subject of my post-graduation study. Abstract:
It is, like the most of bill proposals here (I don't know if in your contry bill proposals are taken more seriously), paused, with no forecast of becoming, one day, voted, much less approved.
In resume, e-books were never charged taxes here, always taken as books and, therefore, with constitucional immunity. (And, anyway, there is no legal prevision for taxes on digital goods, buying Angry Birds on Apple Store is tax exempt too for lack of prevision). But e-readers are charged as a digital device, at least while there are no approved rule in contrary.