The iPad represents the arrival of the viewscreen technology portrayed in 2001: A Space Odyssey. Specifically, the scene where Bowman and Poole were watching themselves being interviewed on a BBC chat show. The devices they were watching look far more like iPads than any other device that has come along so far.
I can see the iPad serving one particular role for me, personally.
Right now, I use a macbook as an alarm clock. A cron job spawns Pulsar to play
There's no reason in the world that this job couldn't be done by a lesser device. Hell, there's no reason in the world that this couldn't be done with an iPod Touch. XM needs to make it possible for their app to automatically start playing your favorite channel when it is launched, and Apple needs to add the ability for the alarm clock to launch an app at a particular time.
Alas, until those two features exist, I have no choice but to keep using a laptop. Because it is an open platform. I have access to cron. cron may or may not be running on the iPhone / iPod Touch / iPad OS variant, but I'll never know because it's not accessible in any meaningful way. And because Apple has such control over the platform, all I can do is patiently wait for them to do what I want them to do (if they ever do).
The closed platform has advantages. There's no malware, for instance. But the flip side of that coin is that there is no Full Tilt client for the platform. Not because Apple would have anything against online poker, per se, but because of the legal quagmire surrounding online poker, there's no way that Apple could approve an app to be in the store without getting dragged into legal hot water. And since there's no other (reasonable) way to get software onto the device, that's the end of it.
I don't mind a closed platform for my phone. The advantages in terms of making the device both resilient and safe far outweigh the limitations. But once we're not talking about a phone, I think the disadvantages of the closed platform loom too large to be ignored.