Stephen M. Hackett on how he arranges his iPhone home screen:
As such, I place my most-used applications in the center of the screen, with less vital ones further out. The green box I overlaid on the screen shot shows the primary target area I can reach with my thumb, while cradling the phone. Since my apps just take up the top three rows, they form a great little rectangle, making it easy to tap the top of the OmnniFocus icon, for example, to launch the app.
An interesting method to be sure, my main problem with the important-icons-in-center approach is that there is no clear memorization for me — in other words I have to look to hit those app icons. Whereas with my four corner approach I don’t need to look to hit those spots.