The PDC today officially kicked off with a keynote by Bill Gates. To me, the more interesting parts came later in Jim Allchins keynote: Atlas, Windows Communication Foundation, Windows Presentation Foundation as well as C# 3.0 & LINQ. However, Office 12 does look very promising too. Can't wait to get my hands on that beta (never expected to say that about Office, ever).
In the afternoon, I attended the following breakouts:
Looking forward to tomorrow, because Windows Workflow Foundation will be revealed at the keynote (aka general session).