Launchpad is the new feature in Lion that makes your Mac look like an iPad. If you haven't yet, click the silver rocket in your dock and check it out. Or better yet, pinch with four fingers on the trackpad. Besides Lion's new inverted scrolling, Launchpad is the most discussed feature of Lion. Experienced Mac users tend not to see the point to it, as they've most likely depend on Spotlight or Alfred to serve as their "launcher". I've noticed that casual users are loving it. As I said elsewhere, the response tends to be, "So, THIS is where all my apps are!" Empowering users to find more apps on their Mac is certainly a huge leap forward. Now, my hope is that those of us who have been using the Mac for years will come to find some good use out of it.
My advice is to simply give it a try. Spend a couple minutes organizing your apps how you like, remove the Applications folder from your dock, and practice the trackpad gesture a couple times. For kicks, I've taken screen shots of my first two pages. (The third is similar to my iPhone's home screen, unorganized and always shifting.) Perhaps you'll find yourself inspired to take Launchpad for a spin.
Page One (click to enlarge)
Page Two (click to enlarge)