The problem most people have is making the choice of what gadgets to carry with them. Already carrying an mp3 player and a cell phone is cumbersome. That is a compromise of what you could be carrying, thus there is a push towards greater integration of function into devices.
The best solution, functionally, is a laptop. It is the general, all purpose, everything available platform. But it's cumbersome, too. And it doesn't make for a good cell phone and is not as portable as a cell phone (concealability, culture trend, cost, etc.)
So what I predict is that devices will eventually diverge onto two paths: the first is the laptop path and the second are devices that integrate a fixed set of functions.
Laptops will continue getting faster, lighter, better. There won't be many surprises here (unless tablets with keyboards integrated into the display become popular, or they become flexible).
But people need the same half a dozen features 99.999% of the time. They are: cell phone, calendar/address book, media player, map/gps, email, document reader and web access with good voice dictation and readout. A fixed function device can be made cheaply and reliably.
Two models will be popular, one with a smaller 2-3" screen and one with a larger 7"+ screen. But, there will be a second trend and it is because of this trend that the device with a smaller screen will be most popular. These devices will become more like the "mother brain" and will use wireless connections to other devices to expand functionality. For example, your car will contain a wireless storage device for music/video playback, a wireless device for reporting car information to your phone and a wireless display which displays your phone visual data on a larger screen in your car.
Similarly in the class room or in the coffee shop you'll leave your phone in your bag (or even in your car) and you'll pull out a thinl, sturdy touch display and do your work from there.
UPDATE:
It wasn't 1 hour after writing this that I saw this video with David Lynch on the iPhone posted on Open Culture.