I love talking to Steve Gillmor because he expands my world view several notches each time. I spent a whole afternoon at the Internet Identity Workshop with him and enjoyed every minute of it. He put up a post yesterday called iPhonomics that says that "[i]n a world post-iPhone where everything changes, battery life becomes the arbiter of usage."
The iPhone will kill the Blackberry. Apple TV will kill the DVR. In Steve's view, the iPhone is center-stage--everything else is a peripheral to it. The secret to understanding this is to realize that more and more, text, images, audio, and video are "cached across the surface area of my environment: laptop, AppleTV, iPhone," in Steve's words.
Of course Gears, Google's project to enable offline Web applications is a key component here--it's not just data, but applications that are ultimately networked, but can function apart from their home environment.
iTunes is a microcasm of this effect. Your iPod is just a cache for what in iTunes, which is just a cache for what's on your shelf or at the iTunes Music Store. The iPhone extends that across multiple modalites.
Dan Farber, extends the battery life riff, suggesting that "with every purchase of a [Starbucks] double latte with soy milk you get access to a charging station." It used to be that free Wi-Fi was a draw, but with mobile Internet cards and devices--like the iPhone--raw power is the thing.