.NET 4.0 will add the concept of Tuples in the Base Class Library, that will improve interoperability between languages such as F# or IronPython and C# or Visual Basic. LINQ will not have big changes in .NET 4.0, but only some lifting to support new features: for example, the Zip operator will be added in System.Linq.Enumerable to combine two collections generating an ordered sequence of Tuples (that you can then project in a different way). Some good examples are described in this post by Matthew Podwysocki.