The Science of Ranking Correlations: How Does PageRank Perform?

I've been an SEO for a long while - nearly 8 years. In all that time, I still haven't been able to wean myself off the intoxicating drug dealt out by the Google toolbar - that "little green fairy dust" called PageRank. Intellectually, I know it's flawed in a multitude of ways, but so many people in our field (and in the broader webmaster/marketing community) still talk about "PR 4 websites" and how "I have a PR6 but he's still outranking me." I find myself thinking about it, using it in conversations and yes, even considering it as a metric for rankings.