There was a lot of great stuff at Web 2.0: Lots of super-smart people with great demos and comments to share.
Lots of panels and presos stuffed with the current memes.
John Battelle being smart.
For me, some moments that stand out:

• Platform apps and Ruby on Rails coming off so cool
• Everyone's take on platform technologies
• Meeting Jonathan Weber of New West and Andy Baio of Upcoming.org
• The cool toys: Tagging, social apps, social networks, mashups, API s for Google Maps