Lorna Timbah

This plugin creates a widget to show the top commentators in your WP site. Always go back to the Widget settings after each version update to Save your settings. Demo can be found at http://demo.webgrrrl.net
The Top Commentators Widget plugin is adapted from Show Top Commentators plugin at Personal Financial Advice, this widget is easier to manage via the control form (no need to edit the PHP file); additional options are also available to make it more flexible. Read the FAQ section on how to customize the widget. Read the Changelog as well as http://webgrrrl.net/tags/tcw for the latest news on this widget.
This widget is extensively tested with the following settings: Google Chrome 13.0.782.215 m, PHP 5.2.13, Apache 2.2.15 (Win32), MySQL 5.0.51a, WordPress 3.2.1. Further testing and bug report on this widget is greatly welcomed and appreciated.

Top Commentators Widget

Adds a sidebar widget to show the top commentators in your WP site. Demo: http://demo.webgrrrl.net

Matteo Manna

This plugin simplifies the life of WordPress users. 
Now users can add or remove their avatar simply using images from his Media Library. Simple to use, no additional functions required. Plugin available on <a href="https://github.com/MatteoManna/Simple-User-Avatar" rel="nofollow ugc">GitHub</a>.

Simple User Avatar

Great

This is just what I needed! Did never like the tie to Gravatar. And the little donation reminder doesn't bother me at all. :)
Kudos!

Great Little Plugin - Clean Code

Simple User Avatar helps users to add or remove their avatar using images from his Media Library.

Top Commentators Widget vs Simple User Avatar