This tidbit is from an older article, but I felt it interesting enough to give another post.
In 2003, Nintendo declared that $34 million was spent on R&D. This figure steadily climbed to $103 million in 2006 and the following year bumped dramatically to $370 million. - WhatTheyPlay
I just said this a few days ago, but it applies once again. You have to spend money to make money. Nintendo poured a ton of cash into R&D for Wii and DS, and I’d say that it’s paying off quite nicely. I am sure that these amounts are just a bit scaled back now, considering how far into the console/portable cycles we are.