I'm holding off because it's just not the same thing. I read a few fiction books a month, I enjoy going to a bookstore, picking out books, carrying them home, reading them, and putting them on a shelf. I enjoy having friends over, and discussing books while standing in front of the shelves. I can lend out my books or give them away. Good books get worn and loved and scratched and used and thumbed. I can place good books in better spots than bad books. And they're all gonna last a lot longer than any electronic books and always be accessible. A book has no bootup-time, no interface, no buttons, no electricity, no charger, no bit-rot, no broken files, no virtual cloud-based shelves tied to an arbitrary account, no uptime, no downtime, no batteries, no keyboards, no nothing.
For fiction, having my entire library with me all the time is useless, because that's just not how I read. I travel a lot, but only carry one or two books with me. That's enough.
It's been a long while since I was in school or university and read textbooks, but the value of having actual paper books that you can write your own notes and drawings in is very high.
For reference books, when I need them, I'm usually at a computer anyway, and why look in a single reference book when I can use the entire internet instead?
DRM? That's at the bottom of the list of drawbacks with e-books for me.