Mission Control is a powerful and handy new feature that provides you with a comprehensive look at what’s running on your Mac. It gives you a bird’s-eye view of everything — including Dashboard and full-screen apps — all in one place. With a simple swipe, your desktop zooms out to Mission Control. There you can see your open windows grouped by app, thumbnails of your full-screen apps, and Dashboard, arranged in a unified view. And you can get to anything you see in Mission Control with just one click. Mission Control replaces Exposé and combines Spaces hot corners and Exposé to a unified experience.
Currently the Launchpad is a bit buggy but since Lion isn't even in beta stage yet, i guess thats ok
A little word to "hot corners" as you see you can trigger Mission Control (All Windows), Dashboard, Launchpad and much more via hot corners. If i move my mouse to the upper right corner, for example, i get the Mission Control View. If i move it to the upper left Launchpad starts. This is a very convient way to use those features besides the Shortcuts, Dock Icons or gestures.