Keynote: everyone will probably have heard about Azure by now. Although this something that's a big deal for Microsoft from a business perspective, it seemed to lack the 'wow'-factor for developers. It will be interesting to see how the pricing will be. That'll be the biggest hurdle to get mainstream-adoption.
BB11 Identity Roadmap for Software + Services: open up the Active Directory-identities to the web using Geneva. AD-identities are translated to claims which can be used by anyone because it's all standards based.
BB09 Microsoft Office Communications Server and Exchange: Platform Futures: I actually did the HOL before this session. Using the managed provider there's very little left to do to build solutions like Automated Call Distribution.
PC21 ASP.NET MVC: A New Framework for Building Web Applications: control the html and separate concerns using MVC. Stackoverflow is using ASP.NET MVC.
TL17 WF 4.0: A First Look: the next version of WF boasts a 10-100x improvement in performance. Seems to be much improved in usability for the developer.
"Show off" is about to start ...
Disclaimer The opinions expressed herein are my own personal opinions and do not represent my employer's view in any way.