I have a 32 GB iPhone 3G S. In it I carry my entire music collection – all 16 GB or so of it. I like portability and the thought of a pocket sized device with everything in it appeals to me. I will qualify for a phone upgrade soon, but although by then I will probably have the option of getting the iPhone 4G, I'm now more and more inclined to simply keep my existing 3G S and get the iPad instead. Even though the iPhone 4G is said to carry a 960 x 640 screen, that would probably be too tiny for me compared with the iPad's 9.7 inch 1024 x 768 resolution, which is comfortable to use. My experience with surfing the net on the iPhone is that it's probably useful for emergency purposes only, which leads me to my second point.
I like big screens with plenty of high resolution screen space. When the new MacBook Pros were launched last month, I was seriously considering upgrading my 13" MacBook Pro (mid 2009) to the 15" i5 MacBook Pro with Hi Res antiglare 1680 x 1050 screen (or perhaps even a 17" antiglare 1920 x 1200 MacBook Pro). But I opted instead for a 24" 1920 x 1200 external monitor. Although a main reason why I got the 13" MBP in the first place was that I wanted portability, it has remained largely a home-bound machine. For the portability, I had even at that time considered the MacBook Air, which is a very sleek machine, but I finally settled for the MBP for cost reasons.
I watch the occasional movie and do very occasional programming in Xcode, working on developing some apps for the iPhone/iPad, if and when I have time to spare. Of course, If I were to start from scratch, I would get a Mac Mini with an external monitor. There is a recent article about it working with two external monitors connected simultaneously. Awesome! If I had a Mini, I would also get two 24" 1920 x 1200 monitors for maximal effect!
The iPad will then be my carry-everywhere productivity device. I'm looking at the 64 GB wifi + 3G. I've already tested and verified that local data SIMs work without problems on my wife's 32 GB 3G iPad. Having tried out her iPad for a couple of days, I've also found its on-screen keyboard quite usable, so I would not need an external keyboard.
I first thought of this Mini + iPad combination and suggested it in a MacUser forum post on February 2nd, 2010. Since then, I've noticed that others have also expressed similar thoughts. Two days ago, I read a TUAW blog that said the same thing. Nice to know that many of us have independently arrived at the same conclusion ;-)