One reason I chose not to use ConfigParser module is that I also have a similar config file for a MATLAB compiled program to run along with my Python script. XML would eliminate the need to use two different style configuration files.
Another reason is that the programmer who is writing the GUI to interface with my Python/Matlab programs must be able to easily read/modify/write these configuration files. Since he is already using XML for other purposes in the Netbeans GUI, this was a logical choice. -- http://mail.python.org/mailman/listinfo/python-list