MacRumors Editor note: It seems obvious that Apple did not develop this "Touch OS X" to be used on the iPhone alone. The Touch OS X technology that is incorporated in the iPhone will almost certainly make its way into a touch iPod, and potentially into other handheld devices.
Considering the prominence they put on the Multi-Touch technology (as revolutionary as the Mouse and Click Wheel?) I think it's obvious that Multi-Touch is the big hidden feature of Leopard. It's also likely the reason that there's been no mention (or hint!) of iLife '07.
It's possible that Apple have built Multi-Touch into 10.5 and are using that technology extensively for the UI in apps like iPhoto, iMovie, Pages, etc.
I don't think we'll ever get away from having a keyboard in front of our Macs, and it's more than likely that the mouse will stay around. But it's not too much of a stretch to imagine that when they announce 10.5 "With Multi-Touch!" they'll announce some hardware to go with it, like a Multi-Touch enabled iMac.
Sure would make Vista (and basically every PC on the planet) seem that much more retro. Like that Star Trek movie where they travel back to the 20th century and Scotty sits down in front of the computer and starts talking to it... the tech guy looks at him funny and points at the mouse and says, "Um, use that!" and Scotty laughs, picking up the mouse and speaking into the trackball...
Multi-Touch is going to put Apple way out front, and with competitors losing steam, it's easy to see why analysists are bullish on their expected performance... Along with Core Animation on the software side powering these things, it's looking more and more like The Future every day. Now where's my flying car?!?!?!