+1 for inc instead of count. appendlist seems a bit too specific (I do not use dictionaries of lists that often). The problem with setdefault is the name, not the functionality. get_or_set would be a better name: we could use it as an alias for setdefault and then remove setdefault in Python 3000.
Just my 2 Eurocents, Michele Simionato -- http://mail.python.org/mailman/listinfo/python-list