My gut reaction to new devices is "don't need it." E-readers, smartphones, tablets, whatever. Don't need it. My seminar on the future of the book has changed that a little. I can now see the place for digital books, and would actually love to have a good color e-ink (not LCD) reader for pdfs and one-time reads. The system isn't set up to work the way I want to use it, though. Supposedly you can use your public library to gain access to ebooks, but even our huge library doesn't have access to the digital versions of anything on my reading list. I'm not paying anything for something I'll read once, even if it's cheaper because it's digital. And Amazon is still missing a lot of stuff. So no e-reader for me for now. The for now is the concession I've made.
One thing that came up in class was the advantages and disadvantages of each form. I got in a match with my professor, each of us claiming that we could list five things off the top of our heads why one form was better than another (he's a digital advocate, I'm dedicated to bound). We didn't actually list five each, but I wanted to make those lists for comparison, so here they are. The advantages of bound books will only decrease with time, but these my current top five.
Advantages of Digital Books
- easily searchable
- more ergonomic to use (due to a lightweight and balanced form)
- conducive to a minimalist lifestyle (fewer physical things to manage)
- easier to travel with (smaller/lighter)
- instant access to one's entire personal collection and also to purchasable content
Advantages of Bound Books
- superior random access 
- cheaper (due to libraries/borrowing/sharing and buying used) 
- easier to consume from multiple vendors
- more accessible interface (no manual, forums, or help needed)
- apocalypse-proof (or able to withstand long-term power-loss/reduction)
I have no idea what is more stainable. On the one hand, bound books mean paper, which means harvesting trees. On the other, we have rare metals (and thus probably fair-trade issues), but also electricity consumption.
I don't think I'll ever go all-digital, but who knows. Even art books might be addressable eventually. The biggest hurdle will be converting my preexisting collection of bound books into digital books. And sharing. I need to be able to share my books without having folks borrow my entire library (i.e. the device).
It basically comes down to cost. I'm not willing to re-buy everything I have nor am I willing to pay 10 to 20x more for a slight increase in convenience. I could deal with everything else if I could get any book for $0.50, which is the standard cost of paperbacks at library used-book sales. Heck, I'd be willing to pay the hardback $1. But as long as the alternative to borrowing a book from the library is to pay an insane amount, I'll stick with my bound books. They need to market books on the app cost scale for real viability; most books should be under a couple of dollars.
 Right now, anyway. I used to be a huge gadget person--I had a PDA in middle school, even though that's obviously not something a middle-schooler needs. Shall we schedule hanging out in the quad for 3:10pm?
 With digital books, there's no good way to hold a finger in one place and flip to another, nor is there a good mechanism for flipping through the book to find non-text.
 One thing that weighs on me is that a shift to digital books makes reading more privileged, at least as currently implemented. Sure, free ebooks are great, but most of the free ones are epub, which Kindle doesn't support. So do you forgo Amazon's selection and go for a Nook? How about an iPad with apps to do everything for $500? Laptops are cheaper. I'm pitching my Occupy eBooklandia tent.