[fjtorres]

I prefer 4x3. One of the reasons I chose a PB IQ as my Android toy.
For multipurpose devices, the best compromise would be 16x10 but even that will have issue.
Ergonomically speaking the key driver is why 4x3 is preferable for portrait reading (and why sigle column landscape is sub-optimal) is scan-width, the distance the eyes have to track on each line.
Where single column landscape requires relatively large font sizes to maintain a comfortable reading experience, 16x9 displays require *smaller* font sizes.
Aother way to put it is that 16x9 displays behave as if they were physically smaller than comparable 4x3 displays.