Depends on what your take on humanism really is... Communism was humanistic but in the interest of furthering the power of the elite and crushing the spirits of the proletariat. Socialism, if it could ever be pulled off properly (i.e., no one benefitting at the expense of others, but rather everyone's work benefitting everyone else equally), might be an ideal expression of humanism...

How this got involved in the Overrated Film thread is pretty impressive...