For "my" developer lunch i selected an awesome session from Microsoft PDC09, called Evolving ADO.NET Entity Framework in .NET 4 and Beyond, where Microsoft's Shyam Pather and Chris Anderson takes us through an hour of as many new features in the new Entity Framework as possible.
Especially interesting is the ability to use POCO-classes (Plain Old CLR Objects) and the "Model first" concept where you remove the dependency to any base classes and begin with the logic tier. Also, with the embedding of LinqToSql into Entity Framework, the rendering of SQL-clauses and implementation of Stored Procedures in the context really takes the data access layer to a new level and remove many pitfalls seen in the past with OR mappers.
Adding to this with the ability to test applications with fake repositories and such i think this is the way to build applications for quite a while.