Don Box has an episode of MSDN TV about using XPathNavigator. If you read his blog, it isn't particularly new stuff, but it was nice to hear him talk about it. Also, I think he explains WHY XPathNavigator is better than other choices in a way that makes more sense than what I've heard before. Good stuff.
BTW, did anyone else notice that Don was using emacs? I thought he gave up on that? :)