Aaron D. Campbell

Used to create a customizable rotating slideshow highlighting certain posts or 
pages. You can choose which posts or pages are featured by simply checking a 
checkbox on the write posts/page screen. The plugin uses the new post thumbnail 
functionality added in WordPress 2.9.
Requires PHP5.

Featured Content Showcase

Used to create a customizable rotating slideshow highlighting certain posts or pages.  Uses jQuery, which comes with WordPress (no conflicts).

tomsinger

A WordPress plugin to create a Featured Posts widget
Features: 
* Customisable title 
* Select categories to choose posts from 
* Customisable thumbnails (none, above, below, left, right) 
* Customisable thumbnail sizes
<h3>Thanks</h3>
Initial image code, customisations and WP_Query refactor from https://twitter.com/_ericholmes to help create a real 1.0 version

Featured Posts Widget

A Wordpress plugin to create a Featured Posts widget

Featured Content Showcase vs Featured Posts Widget