S Hetjens

This plug-in adds the post thumbnail of articles to the RSS and Atom feed via Media RSS (MRSS) specification. Media RSS was 
invented by Yahoo as an extension to RSS feeds used for syndicating multimedia files (audio, video, image). This 
plug-in adds the post thumbnail defined by author of the article to RSS and Atom feeds of the blog. This plug-in 
activates the post thumbnail feature of WordPress, if the theme is not doing it. It is enough to activate the plug-in 
to work, it has no configuration parameters.
MediaRSS is a nice addition to your blog if you want to syndicate your content to other platforms. More and more 
platforms and RSS feed readers support it. The Notes App of Facebook recognize the post thumbnail and displays it in 
every newsfeed item.

Hetjens MediaRSS

This plug-in adds the post thumbnail of articles to the RSS and Atom-Feed via Media RSS specification.

tcloninger

Provides a custom error, using wp_die(), when any type of feed is attempted.
Feature Overview
<ul>
<li>Removal of ALL feeds</li>
<li>Allows for private (more secure) blogs</li>
<li>Works great with the “Private WP” plugin (requires login to view blog)</li>
</ul>
Important Notes
This is my very first plugin. I found it /very/ strange that nobody had done this.

FeedDisabler Plugin

Disables all feeds (rdf, rss, rss2, atom).

Hetjens MediaRSS vs FeedDisabler Plugin