For those of you who are wanting to live on the bleeding edge, Microsoft has just released a beta for the Visual Studio 2008 Service Pack 1. Soma has a listing of some of the new features that are included in this release on his blog. If you want to skip the description and jump straight to the bits, you should be able to download them here.
For LINQ fans, this release is important as it includes the nearly completed first release of the Entity Framework, ADO.Net Data Services (Astoria), and dynamic data controls. I'll likely start exploring those topics here in the near future, so go ahead and check them out if you haven't seen them before.
This release also points to an important change from previous versions of .NET and Visual Studio in that people are often waiting for a service pack to justify moving to a new technology. This service pack appears to be is coming out much faster than previous versions, so hopefully it will only help to increase adoption. Note that this release is only a beta of the service pack. The final release is still pending at this point.