One short year after Expression Studio was introduced at MIX 08 was announced we're seeing a major update to the suite with Expression 2, which shipped last Friday. See here for information on some of the great new features such as PHP support in Web and Silverlight support in Blend as well as things that make Expression easier to install and update and even own via new subscription based pricing.
Expression Studio also has great support via the Expression Community with active forums and great articles, links and training about how to integrate Expression Studio into your design studio.