I have mentioned in the past that Amazon alone could challenge Apple in ways that Google and Microsoft cannot in the tablet arena. As for gaming, they can forget about it. But after play around with the 3DS after I updated it last night, there is something to this dual screen form factor that if done right, can work really well.
So I spent an hour this morning messing around with it and actually started browing the Web on the 3DS. And no, the Web pages didn't magically appear in 3D.
I think Apple needs to continue to keep an eye on Nintendo not just in gaming but should Nintendo learn from the iPad and its 3DS implementation, I think Mario and company can pose a huge challenge to Apple should they decide to really make a run at the iOS platform.