I fretted about which to pick and have advised here that the difference (if any) should be explained on the Python.org download page. I chose ActiveState because I'm on Windows XP, which means that the Win32 Extensions get installed automatically, along with other goodies (the PythonWin IDE, a pretty help file, etc).
If you look at the Python.org download page, the win32 extensions are a separate download: "Windows users may also be interested in Mark Hammond's win32all package, available from Sourceforge. win32all adds a number of Windows-specific extensions to Python, including COM support and the Pythonwin IDE." I have never installed the Python.org binaries, maybe it has a whole 'nother set of goodies, but I'm sure someone here will jump in and explain the difference, if any. The ActiveState version lags behind for a month or two in versions, probably so they can check to make sure everything works together, but right now, both AS and PO are showing Python 2.4.2 rpd -- http://mail.python.org/mailman/listinfo/python-list
