I'm not a futurist as such, but I like to speculate on the paths technology might take us, the unintended consequences of new tech and just plain old what-ifs. I'm thinking that once the world gets a taste of the Apple iPad, the recent crop of e-ink-based book devices like the Amazon Kindle will start to disappear. They may never go entirely away, but the demand for a device that can only read books is sure to diminish once we have devices with comparable battery life and big colour screens that can also play movies on the go.
Mokalus of Borg
PS - Granted, it's going to be as much of a pain getting your movies on an iPad as on an iPod.
PPS - But there will probably be alternatives.