Hi - I upgraded to ctags 5.7 with no change.  But I did finally get it working with the following on the windows command prompt:

ctags --languages=+Python -f python.tags -R "c:\Python25\Lib\"

For some reason all of the following fail on the windows cli:

ctags -f python.tags -R c:\Python25\Lib\
ctags -f python.tags -R c:\Python25\Lib\*.py
ctags -f python.tags -R "c:\Python25\Lib\*.py"

That is, the quotes around the directory are necessary for it to recurse and the --languages option is required to restrict it to python files.  Probably some peculiarity of the command prompt, I guess.

Thanks for your replies, Elias and Elliot.