Apologies to those of you who have seen it before, but I have to mention Iwata Asks - a series of interviews conducted by Satoru Iwata, the President of Nintendo, with the various Wii development teams. And it's not just the usual corporate bullshit - it's incredibly in-depth, and mentions a lot of the difficulties encountered along the way. Well worth a read.
 
Mind you, what I find fascinating about the Wii is that the corporate line - "fun for gamers and non-gamers alike!!!!!1111" - is actually true. The last time my girlfriend played a computer game was back in the early 90s - but now we play together on the Wii practically every day. Which is fantastic.