Scott Guthrie just announced the first public release candidate of Silverlight 2.
According to the blog post this "release candidate includes a ton of bug fix and some significant performance optimization work" and "a number of final API tweaks designed to fix differences between Silverlight and the full .NET Framework".
This RC includes 3 new controls - ComboBox, ProgressBar, and PasswordBox - that will be added directly into the runtime (still 4.6MB). The final release will come with "more polished set of default control template skins" as seen on the pictures below:
Mike Snow wrote a blog post with a list of the known breaking changes between Beta2 and this RC.
P.S.
Only the Silverlight Developer Runtime edition (as well as the VS and Blend tools) are released - this is not the end-user edition of Silverlight. This release is meant to be used only by developers to migrate their existing apps and be ready once the official release launch.