From http://www.enthought.com/python/:
Carrying on Python's batteries included tradition of providing lots of great functionality right out of the box, Enthought, Inc. is pleased to make available Python 2.3 for Windows (Enthought Edition) and Python 2.2.3 for Windows (Enthought Edition), two Python distributions that come with even more useful capabilities already installed and ready for use.
Our goal
Ultimately, our goal is to provide a Python distibution with all of the tools you'll normally ever need already installed and ready to go. So the packages listed above are just the beginning of what we hope will become one of the premiere Python distributions available.