[http://wiki.wxpython.org/index.cgi/PythonCardEditor PythonCardEditor]

Unix/Windows/Mac

Extensible in Python, part of PythonCard.

[http://cooledit.sourceforge.net/ Cooledit]

Unix/X

Extensible in Python

[http://www.crisp.demon.co.uk/ CRiSP]

Unix/Windows

BRIEF-compatible

[http://www.lugaru.com/ Epsilon]

Windows, Linux, FreeBSD, and OS/2

Has Python mode module available upon request.

[http://fte.sourceforge.net/ FTE Text Editor]

Windows, Unix, DOS, OS/2 console, Unix/X

Supports lots of languages, including Python; doesn't seem programmable

[http://www.jasspa.com/ Jasspa's MicroEmacs]

Unix / Windows

Supports Python syntax and a Python-specific menu.

[http://space.mit.edu/~davis/jed/ JED]

Unix, VMS, MSDOS, OS/2, BeOS, QNX, and Windows.

[http://www.jedit.org/ jEdit]

Java

Includes plugin that allows editor scripting using Python (via Jython).

[http://www.jext.org/ Jext]

Java

A Java text editor which offers embedded Python scripting (thanks to Jython).

[http://sourceforge.net/projects/joe-editor/ JOE]

Unix.

GnuEmacs / XEmacs

Unix/Windows

Python support with PythonMode.

[http://www.kde.org/ KWrite]

Unix

Advanced editor for the KDE environment - supports Python syntax.

[http://www.moleskine.f2s.com/ Moleskine]

Linux/FreeBSD

Written in Python, so should be extensible using Python.

[http://nedit.org/ NEdit]

Unix/VMS/Win32/MacOS X

X-Based, Python support builtin.

[http://www.rexx.com/~dkuhlman/ pyeditor]

Unix (and Windows?)

Editor written in Python atop PyScintilla and PyGtk.

[http://quanta.sourceforge.net/ Quanta KDE]

(Unix/Linux only?)

Full-featured web development environment that also supports Python.

[http://www.scintilla.org/ SciTE]

Unix/Windows

Part of Scintilla

[http://www.vim.org/ VIM]

Unix/Windows/MacOS/ etc.

[http://www.slickedit.com/ Visual Slick Edit]

Windows, Linux, Several Unix Flavors, OS/390

Syntax coloring, popup function arguments, class hierarchy browser, other nice Python features.

[http://www.cs.yorku.ca/~oz/wily/ Wily]

Unix

Acme clone for Unix. Can connect to it (and control it) from Python.