Now, before I accidentally incite a PC/Mac war, let me be clear: I'm not necessarily putting my money on Apple as the leader of the New World Order (Microsoft will be a contender, along with the canonical trifecta of Amazon, Google, and Walmart). What I am saying is this: as much as we hear about eyestrain and the doom associated with backlit screens, this is not a dealbreaker for all of us, and further, I'm fairly certain the all-in-one package will soon beat out the dedicated device.
Imagine it: a Mac or PC tablet that integrates full-color books into the existing super-device that is the smartphone (Internet browsing, calling, texting, app...ing, you name it). My bet is that this model will be far more popular than a black-and-white device like the Kindle that only serves one purpose. Sure, Apple (or whoever becomes the Tablet King) will have to overcome obstacles like existing market/mindshare, infrastructure, DRM, &c, but they're a smart bunch. As a result, I don't think Amazon will be quite as monolithic in the e-book industry in five years as they are now.
That said, I'm still interested in the new e-ink models coming out this spring. Sure, you can't watch a video on them or use them to look up that obscure literary reference you just read, but some of them (such as the Skiff and the Que) look pretty sweet. I don't think they'll last in the long run, but I think they're a key part of the ongoing print-to-digital (r)evolution (analogous to Zip disks, laserdiscs, HD DVDs, and so on).
Basically, it comes down to this: I think the Kindle and other dedicated e-readers are necessary to the future of publishing, but they are not going to be carrying the torch for very long; e-books will outlive these types of e-readers by a significant margin.
Next up: dozens of angry commenters who got or gave Kindles for Christmas thronging the comments section! Details at 11:00!