It's true. Not only can you turn off Internet Explorer in Windows 7, but you can turn off basically every major Windows feature—Media Player, Media Centre, Windows Search—everything but the core OS. WTF?
Below is a (lengthy) screenshot of everything you'll be able to turn off in one of the future releases of Windows 7—you can turn off IE8 for sure in the next test release, build 7048, though most of us won't get a chance until release candidate 1. If you turn off a feature off "it is not available for use. This means the files (binaries and data) are not loaded by the operating system (for security-conscious customers) and not available to users on the computer."
But you can turn features back on without popping in that pesky Window disc you're always losing. One of the obvious reasons for the more modular nature of Windows features are all the antitrust suits rippling throughout the land. What feature do you wanna turn off?