Feed(Aggre)gator takes a list of RSS feeds and creates a single list of RSS items from those feeds to be displayed as a widget. You can select how many items you want to display and whether you want to show the entries chronologically or you want to show the latest entries from each feed listed.
You can also opt to display the date associated with the RSS item as well as the author of the item.
<h3>Donate</h3>
If you like the plugin, consider supporting the author through http://www.brownlowdown.net/webdev/feedaggregator/#donate.

feedgator

Feed(Aggre)gator merges a group of RSS feeds into a single widgetized list.

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).

feedgator vs FeedDisabler Plugin