I was lucky enough to attend the Esri Developer Summit 2011 between March 7 - 10th. This was held (as had all the other previous Dev Summits) in Palm Springs, California. Arriving a Los Angeles international after a 13-hour flight was tough but it was alleviated somewhat when a limousine pulled in to take us the two-hours from LAX to Palm Springs.
Wish I went to this summit instead of the user conference. Very relevant and I had a chance to chat to some guys at Amazon Web Services (who were Gold Sponsors at the Summit) about various bits. All I can say is that the future looks bright and it looks like cloud services.
Microsoft was present the highlights include the presentation of the Kinect and ArcMap. Very nice.
Some useful presentations from the dev summit that I found very interesting include:
A Road Map for ArcGIS Server Developers
Advanced Map Caching Topics
ArcGIS Server Performance and Scalability - Testing Methodologies
ArcGIS Server Performance: Case Studies
Architecting ArcGIS Server to Scale
Best Practices for Designing Effective Map Services
Working with Image Services
All the above presentations had immediate relevancy in our work in creating and managing map caches.