Well, allegedly, Nintendo DS specs have been leaked. The juicy bits: 3D acceleration, touch screen, wireless LAN.
My immediate thoughts:
3D acceleration makes sense. It differentiates the DS from the GBA, allows people to re-issue some new old games (Ocarina of Time and Mario 64 handheld?), and, no matter how good Nintendo is at squeezing fun / revenue out of old technology (e.g. GBA, Donkey Kong Country on SNES, etc.), it diminishes Sony PSP's main selling point: superior technology - even if the PSP still has superior horsepower.
Touch screen makes sense. You add a screen, the form factor remains small, something's got to give. You could move / remove some buttons and give developers the option of making their own buttons on the touch screen.
Wireless LAN is puzzling. If you want to do short-range, offline multiplayer, you could just use Bluetooth. Wireless LAN, as far as I understand it, would be overkill in terms of range, speed and power consumption. Also, even more intriguing, WLAN requires a base station with connection to the Internet. Maybe you can use it for direct client-to-client communication (that would certainly be cool for short-range offline multiplayer), I don't know. But it seems to me it would make no sense to release a WLAN-capable gadget without having an online strategy to go with it. In this case, one involving wireless ISPs... how big is that in Japan? An online strategy from Nintendo, now that's revolutionary.
All in all, pretty interesting for a rumour. Nintendo had been hinting the DS would be revolutionary and important. And it had to be, what with the proliferation of mobile gaming-ish devices and the amount of money they made off the Game Boy and it's progeny. But I was wondering what they were going to do. This definitely sounds intriguing.