default

Update: All this is superseded by an existing module, http://drupal.org/project/content_type_overview

Requests for this feature go all the way back to the days of Drupal 4.6, at the least:

create new revision by default
http://drupal.org/node/53149
(4.6 era post!)

This feature remains wanted-- here is the manual instructions, for Stanford.edu!