Handheld Learning - learning with mobile and ubiquitous technologies

In a dream world, I guess it would be a portable, reliable, versatile device that gives the user instant access to data, communications, and productivity resources.

I don't know exactly what a handheld/mobile device is in the "real world" as I hope to explain below.  Maybe the way to do it is to figure out what a handheld/mobile device isn't and then write a definition from what is left over 

Portability-my handheld is portable.  However so is my laptop, unless I need the disk and DVD drives, spare battery, power cable, ... you get the picture.  Then I have to drag a bag w/ me that might as well contain a dozen bricks for all that it weighs.  With the increase in abilities of handhelds (built-in wi-fi & bluetooth, keyboards, cameras, science probes, gps, VGA screens, etc) I am beginning to feel as though I have two laptops!  I can't seem to keep a battery charge to run all of these fantastic items and still avoid plugging in throughout the day.  So much for mobility (unless you count the 5 feet I can walk with my powercord attached).

Reliability-my handheld is reliable.  Unless all of the items I listed above suck the life out of my battery and it dumps my info.

Versatile-my handheld is versatile.  There are tons of applications out there that will allow a user to do just about anything they wish.  Unless I want to share information with someone who is using a device with a dissimilar OS (and I don't own a "translating" program).  When there is some form of "union" between OS's for data transfer, then there will be versatility.

So.... what you are saying then is that mobile is portable but portable isn't necessarily mobile. Interesting thought. The question then becomes, what is your definition of a portable device as opposed to a mobile one, aside from what you say in your post. I think the distinction becomes tricky when you start considering devices that are neither palm-sized (like a cell phone or handheld) nor a laptop. There are more and more devices entering the market that are somewhat in between. In my opinion, we are starting to see a spectrum of devices ranging from PCs to small handheld devices, with everything in between.
Mark