David W. Martin at Cult of Mac:
Apple’s new Mac OS X Lion adds support for a recovery partition as part of the OS installation and while this may not seem important to most users — it is. Apple is making the tools and resources available to you that will allow you to perform disk repair and recoveries on your mobile Mac while on the road or on your desktop Mac at home. The utilities will be readily available and therefore you won’t have to go hunting for that always elusive DVD or USB stick.
While this won’t do you any good if your hard drive physically fails, troubleshooting and dealing with software issues is about to get a whole lot simpler.