Virtual Earth announced during their session that they will release a Silverlight Control for embedding maps in your silverlight app. It will be interesting to see if the silverlight adds any benefit over the HTML/JS control.
Deep Zoom: This is an unmanaged part of SilverLight and not very customizable. The tilingscheme is hardcoded. You cannot create images larger than 4x4billion pixels. That's still enough for having a sub-millimeter precision image of the entire earth, so I think that should be sufficient!
The Steve Ballmer Keynote was very entertaining. It was more of a live interview than a keynote. Rumour has it that the questions he got really upset him, but he hides it very well. WATCH IT!
Other sessions worth watching:
Developing ASP.NET applications using the Model View Controller Pattern
Scott Hanselmans' presentation on WPF user controls was the best session that I attended, and also very entertaining. I talked to him today and he admitted to be nervous which was partly why he kept shooting off jokes. It turned out to be be the best presentation, so it worked out :-)
Developing Cutting Edge Web Applications With Internet Explorer 8
Lots of good tips on changes from IE7 to IE8. Espcially the part about the stuff they fixed that will break existing apps is a must read. Also a bit about new features, XDomainRequest objects, new accessibility features etc.
Creating Rich, Dynamic interfaces with Silverlight 2