I wish I could get both. I've paid for my physical books; I'd like a digital version of each as well. Both have their benefits. Reading in bed, I prefer paper (to get picky, I prefer hardcover, which is why my bookshelf has
a few duplicates). I want to be able to scan an ISBN barcode on my hardcovers and get a digital edition. I realize that could be taken advantage of, but there's got to be a middle ground somewhere. At the very least, retailers like Amazon and B&N who offer printed and digital versions should start including free ebook editions with physical purchases. I might not get my back-catalog built up digitally, but at least I'll be set going forward.
But I love the portability that digital copies provide. I can take my nook to work and read on my lunch break. Don't have to carry a full-size book, don't have to decide on just one book to take with me. Same with waiting in dealer service departments or doctors' offices or anything else. Lots of books, in my pocket.
I do not like retailer-specific publication formats. I love the extra features of Nook Magazines but hate that I can't read them on my phone, which is always with me. I don't like that iPad versions of magazines tend to get extra-extra features over other formats. I'd like an equal playing field. DRM is one thing, but doesn't it make sense to allow as many people to use your store's content as possible? Restricting playback is foolish. I can run Amazon's Kindle app on a hacked Nook (or B&N's Nook app on a hacked Kindle) but there are compatibility issues with "enhanced" titles.
Ebook selections still suffer, too. I can't get C.S. Lewis'
Space Trilogy digitally yet. It's "coming soon" and I've preordered, but it's silly that I can't just get it. I can't get the copyright-Hell-bound Dune Encyclopedia digitally. And it's disgusting how hard it is to find high quality, free editions of public-domain works. You end up paying for the good ones, and the free ones are lazy, PDF-converted scans of someone's stained paperback.
For textbooks specifically, digital is the way to go. Portability (no more lugging huge hardbound behemoths), searchability, enhanced digital features, reduced costs (no print materials to expend)... Lots of win. Plus with tablets or other digital devices, you could have your notepad and your textbook on the same screen. A whole backpack in your hand.