My biggest complaint with the Kindle was that I bought it right before I went on vacation, and one of the e-books I wanted to read on the road turned out to be unusable because it was produced using really awful OCR. How, and why, would you scan a several-hundred-page technical book and then sell it for close to its print price without some kind of minimal check for accuracy? They went to the trouble of separating the tables and diagrams from the main text, but they didn't notice that every minus sign was replaced with a space, and every colon that was printed in a particular typeface in the original was missing from the e-book. It was a recent book, too, so I'm doubly shocked that the publisher used OCR instead of converting their existing electronic documents into an e-book digitally. That experience convinced me to ditch the Kindle and avoid the early-adopter pains.
As an academic, the ability to read PDFs is absolutely critical. I like reading books, but the vast majority of my reading is conference proceedings and journal articles. While I understand that they're hard to transfer (in particular, the two-column LNCS/ACM format), just writing them off seems like a missed opportunity.
I do wonder, if we see a large rise in Netbook popularity, if that two-column format will die. They already look pretty terrible compared to even good web formatting and I can't imagine that reading the PDFs of them on eBooks are going to go without complaint.
I really want to give the Kindle or Nook a chance. I read a lot of non-fiction and having everything on one portable device would be super convenient. The only concern I really have is whether technical books with all their code, screenshots, and diagrams are rendered properly.
I have the Kindle 2, and it's basically a non-starter for tech books. The Kindle DX, though, should be better, particularly if you have PDF versions of your books.
The Kindle DX has rendered all of my PDFs exceptionally well, including graphics. The only issues are that it is only 16 shades of grey-ish and you can't really change the zoom on PDFs (you can rotate the screen to geta little bit of zoom from landscape mode, but that's it)
Why is refresh rate critical? It's not like an xterm has a lot of animation. Maybe scrolling in vim would be awkward. The only problem with refresh I see is that when you type, there would be a delay before the characters appear.
BTW: Someone has got linux running on a Kindle (well, it runs linux anyway... they got access to it).