Here's an excellent analysis by Ricardo Duchesne of the motivations of diversity for the left versus the right.
I'm a big fan of Duchesne's work. I enjoyed his book "Faustian Man in a Multicultural Age" and he's written some great articles on his eurocanadian blog the past couple of months.
Good overview, and I find it hard to disagree with his conclusions.
FMiaMA was a good read too, but rather focused on the academy (which is important, but perhaps not the most pressing area for everyone). It's a bit dry for it. Canada in Decay has more mass appeal, I think. Have you read it?