If you are frustrated by Mail being an RSS reader, and your only RSS feed is Apple Hot News, you can rename the Apple Hot News feed Junk, and the feed will change itself to a junk mailbox under the Junk menu, and the RSS menu will disappear.
[robg adds: I offer this as more of a "huh, that's interesting" observation that a true tip. If you don't want Mail to show RSS feeds, just Control-click on any listed feeds in the RSS section and choose Delete Feed for each. After all are deleted, the RSS section will vanish.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20090529160950544