The Apple “magic trackpad” is the key hardware go-between that will allow Apple users to run iOS (IPad and iPhone) apps under Mac OS X (probably in a virtual container that boots iOS).
Apple’s fans are waiting with baited breath to run their iPhone apps on their Macs. The “magic tablet” makes the iOS touch gestures translate to what until now has been a mouse-centric user interface. Connecting the pocket, lap, and desktop ecosystems will be a big win for Apple.
The huge value to users will be having 500,000 apps available on laptops and desktops, enabled by the Magic Trackpad touch user interface. Many of those iOS apps have few or poor PC app competitors.
Now Apple hasn’t said boo about any of the above. But I’d bank on it.
[Update October 20, 2010] Apple announces it is putting iOS features into OS X 10.7.