While working on our intranet package we needed a fast way to create a couple of nodes without messing too much with the user interface. I just wrote a module (http://drupal.org/project/multi_node_add) that provides a convient way to create many nodes in one page.
This is not a trivial task interface-wise, because usually the content-types has many fields (CCK or other) and here we need to create many nodes!
