In an even nicer twist, when I upgraded to the latest model from my original Kindle, the new one showed up with all of my books already synced so I could literally just open the package, turn it on, and pick up right where I'd left off with the old one. This is pretty small and probably caused more by coincidence based on how the system works than actual intent but it impressed me a lot. I've been a big Kindle user since it came out though.

(FWIW, I use mine to buy books that I previously would've got in paperback form, allowing me to slowly begin the process of rebuilding my physical library by pruning out paperbacks and things I don't care much about in favor of high quality hardbacks.)

No, this is a fundamental difference I believe. Amazon understands the cloud, knows you have leased access to certain materials and lets you read them anywhere.

Isn't it true that media is per-device on the Apple platform? That you have to pay again for each reader you own? Even an upgrade can require paying again.

Connecting with iTunes is actually no longer required for iOS devices starting with iOS 5.

You can also add PDFs to iBooks on the device without iTunes -- not sure about epub files though.

The fun bit about Kindles being registered at the factory is that if you've ever bought a Kindle book before (on an old Kindle or an app) your books get pre-loaded as well. I wish they hadn't released a 3G-less model though; it's a major convenience boost (no need to even think about a network unless you're in a very remote bit of the country)

But iTunes is required to update my ipod to iOS 5 :-)

I've never been able to get large pdf's onto my ipod without itunes. Can't email them because they're too big, and the ipod cannot browse local shared directories.

Dropbox?