It depends on your tastes and lifestyle. Is central air-conditioning worth it? Maybe, if you live where I do, in NYC, where the summers can be brutal, but probably not if you live in Alaska.
For me, the Kindle has been a game-changer for multiple reasons. I’m a voracious reader, and I prefer to own books rather than borrow them from a library or friend (though note that you can check out eBooks from most libraries).
But I live in a small apartment. There are already bookshelves lining the walls. I don’t have room for more printed books. It’s reached the point where I have to get rid of a book if I want to buy a new one, so I love the fact that I can buy as many eBooks as I like. The other thing I like is the cost: Kindles are under $100, which means that if I have to buy one a year, it won’t dent my finances too much (as a middle-class person). They’re pretty robust devices, and I’ve been using the same one for a couple of years, but I don’t get that feeling I get with my iPhone, that it’s this incredibly pricy gadget and I have to be super-careful with it. If my Kindle breaks, it’s no big deal.
By the way, there are various Kindle apps. I have one on my phone, and I also use Amazon’s online reader. I prefer the Kindle, but sometimes I forget to bring it with me, or I want to read on my work desktop (while on my lunch break, of course). Amazon syncs everything, so I can start on the Kindle, continue on my phone, and keep reading on my desktop, without having to search for my page.
Another plus is the fact that most eBooks are significantly cheaper than paper books. Some folks complain that they are not cheap enough. Maybe not, but they are definitely cheaper. And you can often download a chapter for free, to try before you buy.
One final thing: I’m getting older and my eyesight isn’t as great as it was. I love being able to change the font-size and column width whenever I want.
There are some negatives: you don’t have to charge physical books. That said, I only have to charge my Kindle about once every two weeks. It’s instant-on (or rather always on), so there’s no wait for it to boot up. And while I’m not turning pages, it consumes almost no power. (I once went a month without using it, and it still had about the same amount of power left when I next picked it up, even though it had been on all that time.)
eReaders are great for pure reading. They’re not so great for anything else you might like or need to do with books. They have crappy highlighting and note-taking tools. It’s much easier to pick up a pen and write in the margin of a physical book. And if you like to flip around a lot, jumping back five pages, jumping forward, skipping ahead a chapter, Kindles don’t help much. You can do it, but you’ll wish you could just grab a bunch of pages and flip them.
eReaders aren’t ideal for oddly-formatted books. They work best for ones comprised of standard paragraphs. So novels and regular non-fiction books work great. I read some technical (computer) books as well, and they’re not so great. Lines of code are often broken up in strange ways. And, of course, since the current e-ink Kindles are black-and-white, I don’t see color illustrations in color. Some charts and tables are hard to read.
Another irritation is that many books aren’t available as eBooks. If you mostly read contemporary fiction and non-fiction (and well-known classics), you’ll be able to find almost every book you want. But if you read more obscure books, you’ll still have to buy physical copies. Once you get spoiled by “download instantly,” having to wait for a book in the mail (or go to a bookstore and buy one) is a pain in the ass.
Finally, I’ll mention that eBooks give you none of the ambiance of print books. Some people really miss the smell and the feel of pages in their hands. You’d think as the 49-year-old son of an English Lit professor, I’d be in that camp, but I’m not. I don’t care about the form of the book, just its content, as long as accessing that content is easy.
I know many people who skeptically bought (or were given) Kindles or other eReaders, only to find their skepticism melting away as they fell in love with this technology. Like me, they can’t imagine returning to their pre-Kindle lives and read way more than they did when all their books were printed on paper.
Update: environmental impact of ebooks vs paper books: “… purchasing three e-books per month for four years produces roughly 168 kilograms of CO2 throughout the Kindle’s lifecycle, compared to the estimated 1,074 kilograms of CO2 produced by the same number of printed books.” — http://green.blogs.nytimes.com//2009/08/31/are-e-readers-greener-than-books/?_r=0
Update 2021: Six years ago, I moved from a small apartment in NYC (where I’d been living when I wrote the above answer) to a suburban home in Atlanta. I now have tons more space: lots of rooms with walls for shelves. When I first got here, I continued ordering ebooks, but then, suddenly, I found I didn’t want to. I wanted an actual printed book I could hold in my hands, flipping its pages. So I ordered one.
And, instantly, I was hooked. Maybe if I was younger—if I hadn’t grown up with printed books—this wouldn’t have happened, but when I found myself sitting in an armchair, holding a bound volume, I put my Kindle in a drawer and haven’t used it since. I will use it if I ever move back into a small apartment, but hopefully that’s not in my future.
I was wrong. I was wrong in thinking that all I care about is the text, and that it doesn’t matter to me whether I read it on a screen or on paper. I really thought that was true. It seemed true. And it is true that if a book is engrossing, I’ll get into it regardless of medium. But I now know that physical books are important to me. They add to experience.