@Thomas -- True, BUT...
If you know about the page flipping issue, you'd design your app to work mostly in the background, only updating the display when something interesting happens. For example, you could do some kind of mashup with Google maps that shows you types of businesses YOU find interesting, instead of the plain old "restaurants near you" thing Kindle currently offers.
You could write an app that lets you maintain a rating list for places you've visited, for instance.
You could write a P2P app that checks in with a server and maintains communication with your friends, letting you play with the flash mob concept.
You could store all your technical notes in some Kindle-friendly format, and write a search tool for your own stuff, targeted at your job so you can whip through some drop-down boxes and find information you're interested in.
There are all KINDS of crazy things you could do with one of these. IF, that is, the thing is programmable enough.
But now I'm thinking.. Apparently all the native apps on Kindle run on Java! So if you got a console, you could probably invoke the runtime and run your own full-blown apps, with them being rendered with Kindle's built-in widgets. IF, that is, you can get the widget libraries, which are probably in the downloadable source code...
I'm telling you, this thing might be really really neat.
It's a conundrum.