Adobe has just released Adobe Reader 9.0 along with other products. The Windows version is already available for download (RS link), but unfortunately, the Linux version is not ready yet (i'm not sure when will it be ready).
Lots of new features has been merged on this release, including Flash support, more media type, more layout design, and many more. You can see more details on Adobe's website.
Adobe Reader software is the global standard for electronic document sharing. It is the only PDF file viewer that can open and interact with all PDF documents. Use Adobe Reader to view, search, digitally sign, verify, print, and collaborate on Adobe PDF files.