style guideline for naming variables?

[John Salerno]

After reading the PEP, I'm still not quite sure if there is a 
recommended (or widely preferred) method of naming variables. Here are 
the relevant bits:

> Global Variable Names
> 
>       (Let's hope that these variables are meant for use inside one module
>       only.)  The conventions are about the same as those for functions.
> 
>       Modules that are designed for use via "from M import *" should use the
>       __all__ mechanism to prevent exporting globals, or use the the older
>       convention of prefixing such globals with an underscore (which you might
>       want to do to indicate these globals are "module non-public").
> 
>     Function Names
> 
>       Function names should be lowercase, with words separated by underscores
>       as necessary to improve readability.
> 
>       mixedCase is allowed only in contexts where that's already the
>       prevailing style (e.g. threading.py), to retain backwards compatibility.
 >
> Method Names and Instance Variables
> 
>       Use the function naming rules: lowercase with words separated by
>       underscores as necessary to improve readability.
> 
>       Use one leading underscore only for non-public methods and instance
>       variables.
> 
>       To avoid name clashes with subclasses, use two leading underscores to
>       invoke Python's name mangling rules.
> 
>       Python mangles these names with the class name: if class Foo has an
>       attribute named __a, it cannot be accessed by Foo.__a.  (An insistent
>       user could still gain access by calling Foo._Foo__a.)  Generally, double
>       leading underscores should be used only to avoid name conflicts with
>       attributes in classes designed to be subclassed.
> 
>       Note: there is some controversy about the use of __names (see below).

It refers to instance variables, which I assume includes all variables 
that aren't global, and the suggestion is to follow function 
conventions, which would be this:

some_function

But this seems awkward to me. someFunction seems nicer, but it is 
specifically mentioned not to do this for new code.

So I'm just curious how other people handle the multiword situation. 
Underscores, or Pascal case?