Rank 1.0
http://www.chrisvschris.com/rank

To create a Top Commenters list:

<li><img src="%IMAGE%" />&nbsp;&nbsp;%COMMENTER%&nbsp;(%COUNT%)&nbsp;&nbsp;%RANK%</li> 
<?php get_commenters(10, 'ASC', '', FALSE); ?>

or

This is a mixed version without the count:
<?php get_commenters(10, 'ASC', '<li>%RANK% - %COMMENTER% >> <img src="%IMAGE%" /></li>', TRUE); ?>

As you can see it is very dynamic as it lets you choose where you want everything displayed as long
as you keep to the naming convention:

%IMAGE%         - Must be wrapped in <img> tag
%COMMENTER%     - Commenter name 
%COUNT%         - Total comment count
%RANK%          - Rank of the commenter

Explanation:  get_commenters($limit, $sort, $display, $showExcluded);

Default Values:

$limit          = 10
$sort           = 'ASC' 
$display        = <li><img src="%IMAGE%" />&nbsp;&nbsp;%COMMENTER%&nbsp;(%COUNT%)&nbsp;&nbsp;%RANK%</li>
$showExcluded   = FALSE


To insert the rank into a comment:

<!-- Find --!>
<?php comment_author_link() ?>


<!-- Replace with --!>
<?php get_comments_rank($comment->comment_author, '<img src="%IMAGE%" /> %COMMENTER% (%COUNT%) %RANK%'); ?>