Folks asked about XML comments and the DLR. As best I can see, this feature isn't going to be supported with the DLR. The compiler (and IDE) have no idea what the metod that actually gets bound will be, so we cannot give XML documentation at Design Time. That's just the way Dynamic works. When we use Dynamic, the IDE and compiler don't, by definition, know how the call will be bound at runtime, so it doesn't attempt to give us the great support we get for static calls inside the IDE at Design Time. In general, support for dynamic is designed to give us a better option when calling methods dynamically, but there is no denying the advantages that accrue when we link statically at compile time. If you need to call into a dynamic API, then you get better support with C# 4.0 than you had earlier, but that doesn't mean you get all the support available when calling a static method with strict type checking. By the way, and to be sure that no one gets confused, when you are calling Office APIs from the VS 2010 IDE in C# 4.0, you will get good support from Intellisense. Intellisense works when you are calling Office APIs from Visual Studio 2010.
For those of you looking for related material, check out the How Do I (HDI) videos on this page:
Look for the "C# 4.0 Video Series," and for the "How do I use the Visual Studio IDE" series. We also put together some VB videos on the Visual Studio 2010 Beta 2, but they do not appear to be posted yet. There should appear here soon:
For now, here are individual links to the VB posts:
How Do I Use Autoimplemented Properties in Visual Basic will be at http://msdn.microsoft.com/vbasic/ee681550.aspx
How Do I Use Implicit Line Continuation in Visual Basic 10 is http://msdn.microsoft.com/vbasic/ee681551.aspx