Alright!  .NET 3.5 SP1 and VS 2008 SP1 are live and available on the web today.  There are lots of places to read about all the great stuff there, but from the perspective of this blog, the two big additions over the Beta of .NET 3.5 SP1 are:

• Support for multiple texture inputs to shaders used in ShaderEffects.  The makes ShaderEffects quite a bit more expressive and powerful.
• The addition of D3DImage, allowing composition-level interop between DirectX surfaces and WPF.  This feature opens up many, many possibilities of meaningful integration between code that already uses DirectX, or code that is more appropriately written in DirectX than in WPF.

That's just a teaser... I'll describe these in more detail (or link to other resources that do) in upcoming posts.