I saw an early preview of Pablo Castro’s PDC talk about ADO.NET 2.0. Despite only talking about features available in Visual Studio 2005, this talk is going to be very compelling. At a high level, his talk reflects the maturity of these APIs both feature wise and in terms of perf/ scalability.
For those of you already aware of the new features and improvements, I think the talk is still going to be very interesting. Pablo has written several very nice advance demos that push ADO.NET to its limits. My personal favorite is a full featured query processor for the DataSet.