Re: the ecological side - I'm not actually convinced that a paperback book is markedly more of an ecological burden than an e-reader and the rest of the associated infrastructure. I think it's possible the e-reader pencils out in the long term, but I think a full lifecycle accounting of the energy and resources required to create, use, and dispose of an e-reader would be markedly higher than one would suspect, and I think people replace them more often than necessary.
Books, on the other hand, are trees. Bury 'em in your yard when you're done with them and the fungi will know what to do to recycle them.