Which is best for a 10 year old the nook or kindle e reader?

I would recommend the kindle, ONLY IF, you do NOT want your child to play games, watch videos, etc . . . Please remember that the kindle is designed for reading, NOT interactive entertainment. The nook, on the other hand, is specially designed for videos, and interactive entertainment. But if you decide to get a nook, you should get and ipad, this product had millions of more apps. Also, the speed and interface is much easier to use.