after discussion with Eric Firing and John Hunter (see thread "marker
color handling"), I just changed matplotlib.template on SVN:
All the lines duplicating the default values already set in defaultParam
(lib/matplotlib/__init__.py) are now commented out in
matplotlibrc.template (and therefore also in matplotlib, which is
usually copied to the users home directory).
These values have always been redundant and frequently caused problems
when updating to newer versions.
Except for the options backend and numerix, which are both set by
setup.py, the file matplotlib is therefore effectively empty. If a user
explicitely wants to change a value, the line can simply be uncommented
to become effective.
Users of matplotlib are encouraged to use the new matplotlibrc as basis
for their own configuration.