The only one that I have used extensively is Django, which is very easy to use and quite powerful in the arena for which it was created. It has a powerful admin interface that automatically generates data entry forms for content producers and a decent template system. It has some definite drawbacks, though. The admin interface is difficult to customize because it was not meant to be customized too much (Django was written in a newspaper environment, where data needs to go online quickly and be easily customizable for the next story or next year's use). It also lacks ajax support.
I understand that Zope has a pretty high learning curve and is currently in various stages of rewrite. I don't know much about the others. Turbo gears uses Mochikit, which hasn't had a new stable release in some time. I prefer jQuery myself. -- http://mail.python.org/mailman/listinfo/python-list
