First, the problem of eye strain. As mentioned in the comments and in Nathan's Jedi mind-reading mirror poll, most e-reader screens are made with e-ink, meaning they reflect light like a book page does, rather than generating light like a computer screen. Though I'm still warming up to my Sony reader, I have to say that eye strain isn't an issue for me, and I'm curious as to whether the problem of eye strain is generally related to personal experience or is merely assumed to be true based on a perceived analogy between backlit computer screens and e-reader screens.
Second, the price. True, e-readers these days will cost you a bundle, but much like the VCR (remember those?), DVD player, and pretty much any other media device, the price is going to drop precipitously once multiple generations of the machine are available and market penetration reaches a certain point. I voted in Nathan's poll, indicating I'd spend $100 on an e-reader, though to be fair I might drop $150 if I really, really liked it. At $100 for a reader and $10 (roughly) per book, it would only take 15 "hardcovers" to pull a full copy ahead of the p-book game. Observe:
$18 per print hardcover x 14 hardcovers = $252.
$100 e-reader + $10 per book x 15 "hardcovers" = $250.
And I'd recoup my initial investment on the 13th copy ($18 x 13 = $234; $100 + $10 x 13 = $230). True, readers aren't retailing for $100—yet. But eventually they'll get there. Will you buy one then? (I'm starting to feel a little like Sam-I-Am here.)
Third, there's the problem of having your entire library in one place. Admittedly, yes, if you drop your reader in the toilet, you'll lose all your books. Unless, of course, the future is graced by a magical yet strangely ominous entity that ties your virtual library to an on-line account, not an individual reader, so if you order a new reader from them and access your account on it... all your books will be back.
This does not happen if your house burns down with all your print books in it (heaven forbid).
Fourth, resale and lending. Barnes & Noble's newfangled nook (no capitalization allowed, apparently) has a rudimentary lending feature, and there's no reason to think better lending applications won't be integerated into future models. True, resale will probably be forever beyond the ability of the e-book (or, more accurately, retailers will prevent this capability in order to maintain profits... unless they decide to take a cut of whatever profits you make on the resale), but why would you need to resell an e-book? Is it taking up too much space on your e-shelf or in your e-garage? Personally, I don't find this a serious problem.
Agreed, you can't get an e-book autographed—yet. But the first completely wireless, slim, full-color, touch-screen-with-stylus (for my personal annotations and Michael Chabon's signature) reader that comes out for under $200 will have my hard-earned cash faster than you can say "nook." Yes. That fast.