When Microsoft's new version of Internet Explorer ships later this year, it will be set to automatically download its self as a 'high priority' update for Windows XP. Microsoft is quick to point to the improved security the browser should offer. It's not a required update though, you can still opt out of downloading it.
"IE 7 will be the first major update to Microsoft's ubiquitous Web browser in five years. Security was the No. 1 investment for the update, Microsoft has said. Critics have likened predecessor IE 6 to "Swiss cheese" because of the many security vulnerabilities in it. A third and final beta of IE 7 was released late last month."