Web 2.0 Expo in San Francisco was definitely one of the best conferences that I attended. Some 3 hour sessions reminded me of university back in the day. Most sessions were targeted to advanced users and the usual SEO 101 / Web Analytics 101 / PPC 101 were almost completely absent. Unfortunately I missed a few great sessions, but here's a must-read presentation (Powerpoint) of Best-kept Secrets to Search Engine Optimization Success: the Art and the Science.
Stephen Spencer from Netconcepts really pulled it off and his presentation alone was worth the conference pass.