Originally Posted by michaelb
The iPhone is great to use one-handed.
Over the past month I've found myself doing things like eating with a fork in one hand, and selecting music or podcasts, checking email, checking news sites, scanning Google Maps, and checking out YouTube videos with the other. It's even possible to enter characters one handed at least as quickly as using T9 on a regular cell. (For fastest text entry, I use two thumbs typing.)
When using as an iPod, the touch screen is generally more efficient than a scroll wheel, as there is less overshooting the mark when trying to select an item from the menu. Apple's "flick" scroll algorithms are extremely effective for getting from place to place in a list, even using just your left thumb.
You soon learn the technique of "flicking" up or down to get a list moving, then touching to anchor the list when it's reached the right point. It's a very satisfying and efficient use of your energy.
The only serious drawback I've found is the equivalent of the iPod's function where you can press the center button, the track position changes to a diamond, then you can spin the wheel to any point in a track / podcast / video. On the iPod, this is very precise, as you can vary the speed of your thumb rotation to move the pointer quickly or slowly, and can easily get to an exact second in a 30 min podcast, ec.
The iPhone equivalent is to drag a slider bar, like you would in iTunes or QuickTime Player. The serious problem is that on the iPhone this slider is only about 150 pixels long, and the touch resolution is not precise enough to give more than about 40 position points.
The upshot is that in a 30+ min podcasts, you'd be lucky to get within a minute of the time you were trying to, and it gets worse the longer the piece is. (So, for a 20+ hour Harry Potter book, the resolution is appalling.)
This is about the one area where the scroll wheel owns the touch screen bigtime. In most other aspects, the touch screen is more desirable.
It would be theoretically possible to simulate a scroll wheel on a touchscreen. Maybe the 6th gen iPod will have that, or another navigation method entirely. Or maybe Apple will just deprecate the position finding feature.