If you haven't read Jonathan Leger's "Search Engine Myths Exposed" report, you absolutely MUST. It's a great report that debunks the most common myths regarding SEO and the Search Engines. He has case studies and everything. This is will change the way you think about SEO. Oh by the way, it's completely free. And no this isn't some affiliate pitch I am doing. I just think it's a great read for anyone that's interested in SEO.
just go to http://searchenginemythsexposed.com and enter your email. you'll then be emailed the DL link. if you don't want to get all the promotional emails that Jonathan will follow up with, just use a throw away email add.
Interesting stuff, although nothing really new or groundbreaking. The duplicate content part is certainly a bit controversial, since it does matter for weaker and relatively new sites.