I have tagged the first release candidate for v1.4.3 (https://github.com/matplotlib/matplotlib/releases/tag/v1.4.3rc1).
Although this is a bug-fix release, a fair amount of work has gone into making the nbagg (interactive figures in ipython notebooks) feature complete compared to the other interactive backends.
Please kick the tires and give it a try! If there are no major issues, the plan is to target 1.4.3 for next weekend.
The mac build has been started and (if I understand how these things work) should be available to install via
pip install -f http://wheels.scikit-image.org --pre matplotlib soon.
For linux anaconda users, packages for 2.6/2.7 python on my binstar channel (conda install -c https://conda.binstar.org/tacaswell matplotlib). The py3k builds have some issue with invalid syntax in pyqt4, if some knows how to build these, please let me know.