A few days ago my new Kindle 3G (version 3) started rebooting all on it's own. Out of the blue it would restart on its own, be fine for several hours and then it would do the same thing again. It was completely random. I decided to contact Amazon support.
this leather case for the Kindle is defective and causes the devices to randomly reboot. The nice customer service rep couldn't explain why the case was defective nor why it was causing reboots but he did say that Amazon was taking care of customers.
For my troubles Amazon credited back the cost of the original case and then gave me a $25 promotional credit that I could apply towards the use of the Kindle Lighted Leather Cover which apparently doesn't have the problem. Essentially Amazon is giving customers of the original Leather Cover a free upgrade to the Lighted Cover.
It sucks the Leather Cover has this problem to begin with but it's good to see Amazon doing the right thing.