I thought I would compile a list of my favorite OSX features. Keep in mind this is not strictly regulated to Leopard, some of these features have been
around since the induction of Cheetah (10.0)
1. Target Disk Mode - Far and away the best feature of any OSX Mac. By simply restarting a computer and holding down the t key, the computer will boot into Target Disk Mode. This mode is ideal for transferring large amounts of data via a Firewire cable to another computer, or troubleshooting computers, especially those that won't boot. Easily, the main feature for techs that seperates Mac's over PC's.
2. Single User Mode - Another excellent feature to help troubleshoot computers that are not behaving correctly or won't even boot up. Restart the computer and hold down command/apple + s, and it will boot into single user mode. From the command line you can type in any number of commands to try and fix the computer, the most popular is File System Check fsck -fy.
3. Force Quit - When an applications freezes or you get the spinning beech ball of death, usually a force quit will rectify the situation. By simply holding down option+apple/command+esc at the same time you will bring up the force quit option (for PC control+alt+delete).
4. Screen Shot - Something I do on nearly a daily basis is take screen shots to either make tutorials, for error messages, or to grab images that I need. On a Mac this is a built in feature. Simply hold down shift+apple/command+4, the cursor will turn into a plus sign, and then create a "box" around what you want to take a picture of. You will hear a camera go off and it will put a .png file on your desktop.
5. Preview - When I first started using Leopard one of the first thing I noticed are all the changes that were made to it. Before, Preview was Apple's way to open up images/PDF's. In 10.5 not only can you view images/PDF's but you can: crop them, resize them, add effects, etc. With the new features of Preview you can edit a picture w/out ever having to launch iPhoto which will save you a bunch of time.
6. PDF - Another useful feature which I use a lot is to create PDF's. On a PC you would need to have Acrobat Distiller or something like that installed. In OSX, all you need to do is a File-Print, click on the PDF and choose the option you want!!
7. Archive/Compress - If you need to compress large files for either emailing, storage, or some other need, OSX makes it a synch. All you have to do is click on the file/folder, select File-Compress and it will make a zip right on your desktop.
8. Disk Utility - Disk Utility is a built in feature to OS X which got a bunch of new features in Leopard. In here you can do basic trouble shoot by repairing permissions/disk, partition a drive, erase/zero a drive, or create a disk image.
9. Zoom In/Out - A nice little feature to have especially if you are doing a presentation and want to focus on a specific area on your desktop is the zoom feature. To do this enable it in System Pref/Universal Access, and then do the following command, shift+command/apple+minus or shift+apple+plus.
10. Spotlight - Spotlight is a great way to search for anything on a Mac. It also has a bunch of plugins and other features that you can find by clicking on the link. I like that not only does it search the computer, but it will search any document, PDF, or email for words that you are looking for.