Sorry if this seems rushed, but I'm just a little to excited to type right now. The 3DS looks tight as hell, and is doing some pretty amazing stuff (assuming it works). Let's run down the details we got from Nintendo's presser on the 3DS.
The one presented on stage was blue and black with a 3.5 inch screen on top a touch screen on the bottom. Only bottom screen is touch as it evidently messes with the 3D when the top screen gets smudged up from touching. You'll be able to adjust the level of 3D with a slider on the system so as not to give people headaches. It also has motion and gyro sensors built in.
Graphical power is really improved, but no numbers were given and the online seems to have improved immensely. The 3DS will always be connected and update constantly and all online services are free. The portable system also features two cameras on the outside so that you will be able to take 3D photos of yourself as well. The future, people, it is here.
On top of this Nintendo says that the 3DS will play 3D movies as well and has some on the show floor. It also has the biggest launch support from third parties for a Nintendo console ever (more on that later).