http://sourceforge.net/projects/pgf/ shows that 2 days ago (25 Oct 2010) version 2.10 of PGF (Tikz) is released.
What are new functionalities in this version? (not bugfixes, but features)
http://www.texample.net/tikz/builds/ provides a nice overview of what's been happening. Some bugfixes are mentioned, but it's mostly about features. Of course, this is the unstable development branch, not what the actual release consists of, but it could give some pointers to new features.