This Service Pack provides you with all of the functionality you had with our earlier Expression Blend 2.5 June 2008 Preview. Besides allowing you to create new projects for WPF, Silverlight 1, and Silverlight 2 RC, we are also exposing new platform functionality like Font Embedding / Subsetting for Silverlight 2 projects. More on this new functionality in future blog posts.
One thing to note, which is different from how we handled releases in the past, is that Expression Blend 2 SP1 Preview will install on top of Expression Blend 2. This will not be a side-by-side installation. This service pack is also an evolution of Expression Blend 2.5, so there will be no future Expression Blend 2.5 releases.