If a search box could be attractive, Spotlight would be it. You can now drag and drop directly from search results to another program (like Mail) or another place on your desktop.
Previews are new, too--just search for a doc and hover over a result to get an image preview. And finally, you can search the Web within Spotlight and launch a Google search result in your default browser.
Tip: Hit CMD-SPACE to quickly launch Spotlight.
2. More Photo Booth fun
Lion gives you nine new Photobooth effects including Space Alien, Blockhead, Dizzy (blue birds fly above your head!), and my favorite: Lovestruck (pink hearts float above your head). Hit the arrows in the upper-right corner and enjoy these silly, new effects in Photobooth's beautiful full-screen mode.
3. Files and folders are smarter
You'll immediately notice that the Finder is much more organized and intuitive. There's a new All My Files view, which (obviously) displays all your files organized by type in a pretty interface. Apple also added a smarter search box, and the ability to swipe though files in the icon view.
Folders are more intelligent, too. When you try to combine two folders with the same name, Lion will ask you if you want to merge them. Also new is a feature that lets you create a new folder from a selection of files.
4. Your screensaver is a jukebox
When your iTunes' library artwork is your screensaver, clicking on any album will immediately launch its music. Go to System Preferences > Desktop & Screen Saver > and set is as "iTunes Artwork." Hit "Test," click on any album cover, and jam out with this awesome feature.
5. Add a login message
What happens if you lose your laptop? With Lion, you can add a message to the login screen, so make it useful by adding some personal information (like your phone number or e-mail address). Go to System Preferences > Security & Privacy > General. Check "Show a message when the screen is locked" and add your info in the box below.