I would just like to say that Sony might be making a huge mistake again by judging the 3DS as they had with the NDS. Do note, I am quite a major Sony supporter but i have my justification.
Firstly, NDS is not only played by children. I can safely say at least 25 - 50 % of NDS users are adults, of at least 20 years of age. Still, 3D does not only appeal to adults. Kids in the current generation are much much more advanced and technologically way smarter (when it comes to technology usage). They will compare and contrast. With 3D movies mostly the rage now, kids will in a way demand and want to have 3D on their gaming device too.
Next, when the NDS first came out, I remember a lot of backlash against it and Sony did say something along the line like the DS wont succeed because it appeals to kids only while the PSP will because it has the better processor and such. I can assure you that is not very true. Graphics make part of a game depending on the situation. I myself got a PSP immediately when it came out but I did not even thought of getting the NDS. until I cant get over the urge to play pokemon and final fantasy on it. Thus i bought it. And there are so many fun games on the NDS without the top notch graphics. I was hooked on advance wars and tried to clear every single map in campaign mode.
Thus, saying the 3DS will not succeed because it appeals to a different demographics is quite I feel a grave human error. I have a feeling that the 3DS is going to succeed massively and continue on like the NDS.
Do note I am neutral when it comes to Nintendo. I have some love for it, no hate, but my love is definitely for the PS3.