A very nice list of debuggers, but I'm wondering why there is no mentioning of the (very good) debugging support you can find in IntelliJ and Eclipse and mostly, why there is no mentioning of Winpdb [1]; a very nice and platform-independent Python debugger with a full-fledged GUI.
Mostly because I'm a VIM + command line type of guy :)
I'm aware there are a slew of plugins/built-ins with IDE's that I didn't cover. As I mentioned in a comment on the post, I think a disclaimer that stated my preference would have helped.
[1]: http://winpdb.org/