Even the basic python interpreter can tell you about the modules you're using:
$ import Maya
$ help(Maya)
$ dir(MAYA)
That said, my favourite set up generally is Eclipse + PyDev extensions. It gives a full IDE environment plus debugging with check-pointing, stack inspection, module completion; the lot. It's pretty easy to get going on Linux with a proper package manager.
Here's a good (on Windows) setup guide:
http://www.vogella.de/articles/Python/article.html
For just small tasks, I prefer 'scite' (GUI) and 'iPython' (command-line). Scite runs your coding-in-progress in a command buffer by hitting 'F5' and iPython has code-completion and other goodies like proper tab/white-space handling. iPython is probably the best 'hard-core' tool of the lot.
Editra is what I use when I'm on a Mac or Windows. It's a lot like Scite.
IntelliJ if it's got better Python support would be the best of the lot. It is an absolutely wicked Java tool for messy things like refactoring. I haven't tried it in a couple years.
Netbeans has some Python support these days that might be nice. I got burnt by that tool ages ago and won't look back. The same goes for Xcode.
Finally, here's what our 'sister' site had to say:
http://stackoverflow.com/questions/81584
/p
ps: vi, not emacs :D
EDIT:
There's a new/cool looking Python IDE on the scene: http://www.jetbrains.net/confluence/display/PYH/JetBrains+PyCharm+Preview
By:
Paul Nendick
[ Editor ]