I tried Mac OS X Lion and it is kind of direction PC suppose to move on.
These are the mail agenda for new iPadish mac,
1) Simplify things and use more intuitive user inputs like multi touch gesture ( + voice ) to interact with system.
2) System needs to hide file explorer or hunting among the tree of folder to locate things.
3) Home screen should be your app store for your regular usage, yes that's what you go to frequently and start what ever apps you want to consume or produce. This is user level app store and user governs what they want and it is single door to his/her system. I feel it is right direction for apple to go by embracing the iPad model.
I looked at NY times skimmers it's navigation is kind of borrowed it from gestures (touch) of Macbook air (Lion). It feels better and evokes psychological feeling of native to the OS as OS itself based on gesture inputs.
So what is the difference between iPad and Mac? In macro level there is not much to normal user except few reminiscence like ports and file access until it is fully cloud enabled. But one glaring exception is Mac is unlocked. You have a freedom to use your system as you wish to the certain extend. It feels like unlocked iPad and it is unlocked iPad.