Let us not forget the Apple Newton Emate 300:

http://en.wikipedia.org/wiki/EMate_300

Probably the best computer ever designed for children. I used one myself in school from 4th grade through 8th grade when I upgraded to a "real" laptop. The main reason for the upgrade: I couldn't program on the emate. Other than that it was in every way superior: Instant on, touch, nice keyboard, no distraction interface, usable in all lighting conditions, ect...

Now of course people would sneer at it since it didn't have any form of internet. However, at the time my teachers were more comfortable with it in the classroom due to those limitations.