The 3DS could be Nintendo trying to steal some of Apple's market as Apple is trying to do to them...
We already know that it is a dedicated 3D gaming machine with internet access, and some form of Netflix access (I'm gonna go out on a limb here and say that Netflix movies aren't the only playable movies). Throw in VoIP, mobile TV, music, an app store that sells more than games, an e-reader, maybe bluetooth, keep it around the size of the PSP while folded, and suddenly people may be looking at buying a 3DS instead of an iPhone 4G--if they market it properly and bundle AIM(or something else) in there so people can still text. The 3DS's top screen is likely going to be .1" smaller than that of the iPhone so if it can do everything it does, plus do 3D and serious gaming they would be in the same market.
Of course if I'm going to imagine that Nintendo is that ambitious, I might as well imagine them partnering with Google and running Android on 3DS so the app store is full at launch, VoIP becomes easier, and Apple fan-boys would be in a rage.