Slow down there, Tex.
I have a Kindle. I LOVE my Kindle. I've convinced several other people to buy Kindles. If you like to read, I encourage you to buy one (I've read twice as much since getting mine 3 months ago). But I do not think the Kindle, as it exists now, will replace anything, much less textbooks for the immediate future. It just isn't good enough.
Benefits (let's start with why you should get one):
--lightweight (10.3 ounces; and yeah, no matter how many books you put on it it stays 10.3 ounces. At the pre-college level, states have even passed textbook weight laws, so this IS a benefit for education)
--holds a lot (like 250 books natively; mine hold 3000 with the memory card)
--small, easily portable
--lots of cool in-book features (bookmarking, different font sizes, looking up words in the text instantly, annotation, clipping, text searching, etc)
--long battery life
--easy to read in most lighting conditions (even in direct sunlight, which back-lit screens cannot do, but no built in light)
--potentially greener than books
--fewer stack of books cluttering up your home
--ability to download books, newspapers, and blogs over cell phone signals (and quickly)
--I personally find it easy to read and hold (though some complain about both screen size and no good place to hold it)
BUT...at the end of the day, the device is still essentially meant for reading linear, straight-forward prose--fiction, biographies, etc. This is important to keep in mind when speaking of the Kindle, particularly as it relates to college and school books.
--The Kindle is NOT in color. For some subjects this doesn't matter. But for others, science books use a lot of color-coded images where the red arrow means heat and the blue means cold, or geography uses a lot of maps with different colors showing different states or industries, etc.
--The Kindle is NOT the best resolution. It is 800x600 at 167dpi. For what it is, it is great, but that doesn't mean that it can show all that many images all that clearly. (I downloaded the new John Hodgman book and the pages that are images are useless).
--The Kindle is linear. It has no good way to handle content in margins, for example. And how many textbooks use a LOT of marginalia? And it certainly has no good way to handle the sidebar/wrap content in a Teacher's Edition of a book (the part beside the page with the answer keys, etc). Also, it is harder to thumb through a Kindle or jump to another page you need without knowing where it is. Prose you read straight through, but in textbooks you often bounce around. Even the device homepage can become convoluted and hard to navigate as you junk it up with downloads.
--For offering some advantages, it does go as far as classrooms would like. Just holding books is nice, but teachers will desire it to be able to host and send back tests, quizzes, and surveys, for example, which it cannot do; to serve other purposes than JUST reading.
--You lose the Kindle, you lose all your books, not just one.
--You break the Kindle, you lose all your books. Books don't often "break" when dropped three feet, but a Kindle may, and it will take with it everything--your books, your bookmarks, your notes, etc. The first gen case is inferior and the device tends to jump out of it a lot. I see a lot of "I couldn't read the assignment, my Kindle ate it" type of excuses.
--Not all titles are in the Kindle. For some time, this will be the case. And then you have to think of the economics. Some people will benefit and want it, but some will lose money and fight it. For example, authors and publishers will make less for each book because they'll have to sell them for less. But bookstores will make less because there will be no market for "used" textbooks, nor any used Kindle books to buy. All sorts of issues around economics and rights management issues need to be hashed out for this specific marketplace before it will go forward on the platform.
It IS cool. And who knows, someday, this technology may become a leader in the education marketplace as it does solve many problems (weight, cost, etc). However, the device is several generations of development away (both in soft- and hardware) before it can practically tackle the needs and wants of such a market.
"I already own a lot of e-books, but to put them on the Kindle I'd have to repurchase them through the Amazon service. I think that's ridiculous."
Then blame the publishers, not Amazon. Your ire is misplaced.
That's like blaming Apple because the iPod has a proporietary format. But it also takes mp3s. If they other provider had a proprietary format and didn't give you a universal mp3, that is their fault, not Apple's.
The Kindle does take PDF files. So, if the person that sold you the book originally gave you a PDF, the Kindle will take it happily. If the originally seller gave you a proprietary format...well, that's what "proprietary" means. You can't blame Amazon for that.