Just had a conversation with my wife about the Kindle-Fire (KF) and had an epiphany.
KF isn't a replacement for the full tablet, but it is a replacement for the smart phone!
KF costs $200 plus zero for service contract
smart phone costs $50-$200 plus at least $30 a month for data contract.
If you mostly use the 'smart' features of the phone for things like email/calendar/games, then it may be very compelling to ditch the cellular data plan, ditch the smart phone, get a dumb phone for making dare-I-say-it phone calls and the KF for email/calendar/etc.
I think we're going to do that.
OTOH, if you want a tablet for creating rather than consuming content, you still need a full size tablet, preferably with a keyboard.