Norbert,
Your change in commenting out almost everything in matplotlibrc was a good one, but I think it had an unintended consequence: it changed the way everything looks because the defaults in __init__.py were not the same as the ones in matplotlibrc. To my eye and on my machine the matplotlibrc defaults are better, and my guess is that this is because over a period of time people tuned the matplotlibrc values but left the __init__.py values alone--after all, they were normally not used. In any case, I went ahead and changed __init__.py to match matplotlibrc.
Eric