I've been thumbing through the Perl Hacks
book lately. Some of the "Productivity Hacks" are (nearly) applicable to Python as well as Perl hackers. For example, most of "Hack #5: Autocomplet Perl Identifiers in Vim" applies directly to Python vim users. I've been using the CONTROL-N thing for years now. Basically, if you have a "word" in a file that you are vimming, you type the first couple of letters of it, hit CONTROL-N, vim will match and complete that already-entered word. But, as chromatic pointed out, it won't match (in Perl) "words" that look like "Foo::Bar". Nor will it match (in Python) "words" that look like "foo.bar". The solution to this for Perl is to add "set iskeyword+=:" to your .vimrc. The solution in Python is to add "set iskeyword+=." to your .vimrc. Actually, I added this to my ".vim/ftplugin/python.vim" so that this would only get loaded when I'm editing a Python file. Now, I have greater joy in my vimming experience.
Anyway, this was a great hack that was easily modified to work for Python. There are other useful hacks that are very applicable to Python folk. I don't know how many of these I want to give away for free, though. I might make you go buy the book :-)