E-books are preferable (though on the PC; I don't have an E-reader). There is nowhere comfortable for me to sit while reading a book, and reading in bed is impossible: I fall asleep immediately.
Books are for when I want to read outside the house. Otherwise they're only good for endnotes. Going from page 20 to an endnote in a non-bookmarked pdf is a monstrous ordeal.
Finally, physical copies are too rich for my blood. I have no idea where to find these used book stores, so it's either Amazon or the library for non-digital.
Bookmarks