[serpicolugnut]

1. Stability.
2. Ease of use. Really. After you get past your OS 9 hangups, you can navigate much faster through the OS X Finder. Sure, it needs additional work, but they got more right in version 1.0 than wrong.
3. iApps. Can't overlook this. Without great iApps like iMovie, iTunes, iDVD and iPhoto, the OS wouldn't be half as useful.
4. Did I already mention stability?
5. Cocoa. Thanks to Cocoa, rapid application development is a reality. In one short year we have gotten some great shareware apps out of developers using Cocoa. Watson. osXigen. Pic2Icon. Duality. PixelNHance. OmniWeb. Snax. This list just keeps on growing.
6. Java. Having the best Java support is a huge plus. I get a grin when I run an app like LimeWire on my PBG4/500 - because it runs so much smoother and faster than on my PIII800. And we're only at the beginning!
7. Having access to a command line when needed.
8. The speed in which 3rd party developers have rushed to make OS 9 missing features available in OS X (Unsanity's Haxies, ASM, DragThing, DefaultFolderX, Keyboard Maestro, TinkerTool).
9. The Power of UNIX. It's just incedible that with UNIX under the hood, a Mac OS X user can 1) Run X Windows and the vast majority of UNIX software, 2) Run JAVA 3) Run Classic Mac OS apps, 4) Run legacy NeXT apps through Cocoa, 5) Carbon apps, and through 6) VPC, any x86 OS and application. Amazing.
10. The Dock. While it's FAR from perfect and needs some major adjustments in my opinion, it's a good start. Give us options like the ability to turn off the floating titles (or have them appear with a yellow background , ala tooltips - the white w/ shadow text is too harsh over anything other than a dark background), ability to access stuff from the Apple menu when right clicking on the Mac OS Logo in the Dock, and the ability to have "Tabbed" groups within a dock, ala Drag Thing.