My 8 year old is getting one. At first she wanted a Fire but after researching it she decided on the basic no-frills Kindle 4. She's a voracious reader so I'm certain she'll use it a lot. I haven't chosen a cover/case for it yet. When she turns it on the first time she'll find it pre-loaded with books she hasn't read as well as a few favorites.
I think I'm a little bit too excited about seeing her face when she opens it. Wait, nevermind, I'm not.