Not much really, the Kindle 3s perform exactly like our former Kindle 2s, except of course for the lack of 3G connectivity. Ivette probably had an easier time with it, in my case I kept looking for the power button in the wrong place.
The new lighted cases are really frickin nice (and the leather looks much nicer than the second generation cases), and so is having the closing band. I put velcro behind ours to keep them from straining the hooks. Ivette uses the light much more often, almost on a nightly basis.
As for the screen, it is definitely superior to the screens in the first two generations.
Battery life is incredible, even with wireless turned on. As for the lack of 3G, it is a non-issue, since I travel so little. In the remote possibility that I do hit the road, I just avoid deleting books like I used to (easier since Amazon introduced collections). In the remote possibility that I finish a book, I can read something else I got stashed. Or worst case scenario I can stop by one of the million Starbucks around here and use the AT&T WiFi for free.
Would I still recommend the Kindle 3 WiFi? Yes, as long as you are not a commuter. If you are a commuter, get the 3G. If you just like to read and mobility isn’t an issue, then there is no reason to pay extra for something you won’t use.
What about a surplus or used Kindle 2? If you can get one, go for it. There is nothing wrong with the second generation Kindle, and the free 3G service is grandfathered to the device, it is not tied to user accounts. As long as the device is alive, it’ll have free 3G until Amazon shuts them down.
And what about a Kindle 1? Sorry, but these are going to be a little long in the tooth, and the first generation screens are much more delicate.