AppleInsider has an article on the wider possibilities of multitouch for Apple beyond the iPhone. While the positioning of this as being a "mega-platform" feels a little like jargonitis, the idea makes perfect sense.
The article is more focused on the effect this could have on Apple's share price than on customers but the change in possible user experience is surely the big story here.
While OS X is already pretty much a doddle to use, all OS-es are now reasonably similar. And most mice have just about as many buttons and wheels as they can handle. Multitouch offers the chance to have a far more intuitive interface with way better use of screen real estate – running out of room? Just pinch. It also offers a change in mindset where the user is closer to the action, not having to act on the screen through other attached devices.
Whether this will do for PCs what the iPod did for MP3 players remains to be seen but I'd be very surprised if we don't see a multitouch iMac before too long.