FileVault 2
Apple’s often-maligned built-in encryption service is getting a much-needed kick in the pants with Lion. In addition to encrypting your entire hard drive rather than just the Home folder, FileVault 2 will also let you encrypt external USB or FireWire drives as well. Encryption has been optimized so you can continue to work as FileVault 2 does its thing, and use instant wipe to cripple your data in the initial pass, then wipe the drive completely in the second.

iCal
Although it was seen in a number of the Mac OS X Lion slides displayed during the WWDC 2011 keynote, little was said about the revamped iCal, which now takes on the look of its iOS sibling. But there’s more than that -- iCal finally gains both a day view as well as a year view, and even a swanky “heat map” view so you can prepare yourself for days where you have too many events. And of course, some full-screen goodness is also part of the new iCal.

iChat
If you’re not content holding chats with friends on AIM, MobileMe or Google Talk, you’ll be happy to know that Yahoo! Messenger is joining the iChat party with Lion, bringing with it both a unified buddy list as well as status. Organize your chats with moveable tabs, tag your buddies with iPhoto pictures and developers can now create service plug-ins for iChat, no more crazy hacks required.

Preview
Since it’s included with Lion, Preview already gets the cool full-screen mode, Versions and Auto Save support -- but did you know that iWork and Microsoft Office documents can also be opened, searched and printed with Preview? You’ll even be able to add your signature, copy and past images along with text in PDF documents and control shadows and highlights.

QuickTime Player
Finally bringing back some of the functionality lost in the move to 10.5 Leopard, QuickTime Player now lets you combine multiple clips into a single movie (just by dragging and dropping them to a movie window!), export audio only files, rotate video, show mouse or trackpad clicks when capturing the screen and even share videos directly to Vimeo, Flickr, Facebook, iMovie or Mail.

Safari
Developers just got their hands on a Safari 5.1 beta, and there’s a host of tasty treats in store for us when Lion finally arrives. HTML5 support gets up to date, along with MathML and Web Open Font Format (WOFF) support and CSS3 tricks like auto-hyphenation, vertical text and text emphasis are added to Safari’s feature set. The Downloads list even gets some love, including the ability to drag and drop downloaded files right to the Desktop.

Screen Sharing
If you have multiple computers in your home -- and maybe a Mac mini tied to your big-screen HDTV -- Screen Sharing is an invaluable way to control them from elsewhere. Lion adds some cool new features to the service, including full-screen view, using an Apple ID to authenticate, a stealth “Observe Only” mode and a new screen-sharing toolbar to control clipboard access, screen capture and more.

System Preferences
We know it’s not the sexiest part of the operating system, but System Preferences gets some love in Lion with the ability to set up online accounts from one place (including Microsoft Exchange, Gmail, Yahoo! and AOL), cool new desktop pictures, scroll direction preferences and even the ability to turn app indicator lights in the Dock off. Who doesn’t like those little glowing lights?