Iwata asks is the best. Usually. This one, focusing on the Wii U's development, is a little bit strange. They spend an unhealthy amount of time talking about the console's power consumption and how they've managed to reduce. Look man, I'm all about saving the planet, but there's a time and a place!
Still even if you're not into that level of detail, like myself, you might be interested in the numerous different pics of what the internals of the new Wii U looks like. Also -- there's a completely ugly transparent Wii U to look at.
Iwata Asks: Wii U [Nintendo]