P. Chandra

Adds copyright notice at end of articles in full text RSS feeds, with back links to the blog and original article.
A notice gets attached at the bottom of feed articles like this 
Original Article: Title of Article (linked to permalink) 
Copyright Year. Blog Title (linked). All Rights Reserved
Your Blog title is linked to your blog Url. Your article title is linked to the article permalink.
Blog copyright notices are important as your feed gets freely distributed across the web and is republished without permission by RSS scrappers and autoblogs. After using this plugin, now RSS scrappers will link back to your site, which will suggest to search engines that your blog and article was the original source.

Simple Feed Copyright

Adds copyright notice at end of articles in full text RSS feeds, with back links to the blog and original article.

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).

Simple Feed Copyright vs FeedDisabler Plugin