Children, children everywhere...
To me this is a big one. That transitional age for my son---6 or 7 years old, way too young for a phone at this time---BUT there are a ton of iOS games, educational apps, Netflix, youtube walkthroughs for his game...downloading a couple of videos for flights, the list goes on and on. I got him a 32GB iTouch last fall (after he spent a week in the hospital due to an asthma attack, something that he'd NEVER had before)...after making the deal with him that if he beat each small battle in the hospital (IV's, medication, respiration exercises, et al), he'd win the
War!
...he complied, is a very healthy young boy now, hasn't had an attack since. We went right from the hospital upon release to the Apple store, let him pick out his iTouch (color), a case and a $25 app card. I set it up in my name/Apple ID, so he's welcome to any and all apps I've purchased (that are child friendly). He's taken excellent care of it...other than the 'boogers' we've got to wipe free once in a while

It's easily his favorite 'toy'....but he's extremely mature with it, realizing it's
not a toy...something we explained to him when purchasing it...that it was his first "Big Boy" item and it had to be handled as such.
In this day and age...as another poster mentioned, kids are born 'connected'. Give any 2 or 3 year old an iPad, show them the basics and they're off an runnin'! I think, with the proper apps...these can be powerful learning tools, excellent dexterity 'helpers', and extremely entertaining. Obviously, everything in moderation...but living in Alaska, if we want to go anywhere...flying is our only choice. We leave two or three times a year, this year--we've flown 3 times. I bought a small extra battery pack that fills up the iTouch almost 3 full charges and I can't tell you how invaluable it's been for layovers, long flights, and general boring time-periods. We also have a cabin about a hundred miles north of Anchorage....this road trip is another excellent time for him to be able to play with it.
In my opinion, technology can never be taught to a child too young. It's such a ubiquitous part of our lives these days and I wouldn't be surprised if tablets begin to take over the 'paper' at schools sooner than later.
I still have a Gen 2 Black and white iPod in my truck that lives under the dash with a couple thousand songs essentially hard-wired to my stereo. I've also got 3x160GB Classics that we use as a tertiary backup in our business (we run a mobile audio company)...with a massive backup library in the case one of our computer systems go down. Much easier than burning, maintaining, and transporting a box of 'Best of' CDs everywhere
YMMV....But I've got a ton of reasons, and I, too own an iPhone (as does my bride) and iPad (as does my bride)!
J