Dead tree books, no batteries required.
E-books. Very little 'lektrikity required.
I've got lots of dead tree books, some printed 100 years before I was born. Many more that I bought in airports right before a flight. Some from estate sales I went to in the '80s and bought libraries in whole lots.
I'm comfortable buying e-books and reading them. I find them to be more handy and convenient than my shelves full of books.
I guess I am in the middle here. I like being able to carry around a library in a tablet; but there is also something to be said for Dead Tree books. There is a whole other experience to reading missing from e-books. The texture of the paper, the typeface, the solid weight of the book, the binding, the tactile feel of turning a page; all of these things add to the art of reading.