I got an iPhone when they first came out. The original iPhone. I have since upgraded to 3G, and now 3GS. I consider it the greatest techno widget I have ever owned. The sheer magnitude of the functions it performs is staggering. Consider, as a frequent business traveler, the difference between traveling to strange cities alone in the mid-seventies, and traveling with the iPhone now.
Then: Get a map at the rental car counter
Now: Key in destination for turn-by-turn directions
Then: When you get to the hotel, call and give phone number and room number to spouse
Now: Place safe arrival call as soon as you land while taxiing to gate.
Find a place to eat:
Then: Ask desk clerk at hotel, or read hotel guide
Now: Bring up location based services app such as Around Me, Zagat, or Yelp
Then: Find a place to call police
Now: If phone not stolen, use phone to call 911. If phone stolen, use computer to find phone.
To be fair, there was a period when I had some of these before iPhone. I had an IBM x40 Thinkpad (very small and light). I had a USB connected GPS and Delorme Street Atlas. It would give me directions, show points of interest, but it always took a few minutes to get it going, was difficult read in bright sun, and the biggest thing, it wouldn't fit in my pocket. Small as it was, it still needed an over the shoulder carry bag.
What the iPhone did for me was replace all of the needs to carry a computer when traveling unless it is needed for business. For me, the only significant issue with the iPhone was that it's small size causes eyestrain for this old man if I try to read for a long time, watch TV, or anything like that. I wished it could be just a bit bigger.
Enter the iPad
When I first started hearing rumors about an Apple tablet, I was really excited. There were a lot of different screen sizes rumored, and the one I so fixed my thoughts on was one that would be about 5x7 in size and had all of the hardware, including the phone, that came with the iPhone. It would still be small enough to be carried in a pocket (such as a vest pocket in a jacket), but would be large enough to be read as easily as one of the millions of paperback books of that size.
What Apple announced is cool, really cool, but it is too big. For my lifestyle, it's imperative that it fit in a pocket. I want a senior size iPhone. If one appears, I will trade my existing iPhone for it. Until then, even if I buy an iPad for whatever reason, I'll still need my iphone as the current iPad will not replace it. The iPad, as announced, will not revolutionize my life the way the iPhone has.