The aspect ratio of the iPad is 1.333:1 and the iPhone is 1.5:1. I propose the following for both-- 1.414:1. You math folks will recognize the root-2 ratio. This is the ratio of paper that pretty much the whole world uses, except the stubbornly backward US. The brilliant thing is that when you divide the screen in half, you are left with two rectangles that keep that proportion. This would make pane-splitting very practical. Two applications can run in side by side and they would fill the screen perfectly. Also, if the ISO-A5 is used as the standard for the iPad (very nearly the current size, just about half an inch longer), then items would even be to-scale that were drawn on paper to-scale. Additionally, the width of the screen in landscape would match, in full-scale, the width of an ISO-A4 page: the most common paper size in the world. There would therefore be no better way to visualize the printed size of document, since it would truly be precisely the size of the printed page. Similarly, the iPhone's screen should be ISO-A8, which would make it exactly 1/8th the area of the iPad with the same proportions-- also to-scale. In an environment where we are constantly flipping orientation, wouldn't it be nice if there were some sense behind the scaling and proportioning? And this would also create better interchange between the iPhone and iPad. As for pixel count, 1920x1360 works out beautifully. This enables 1080i/p to be displayed at full screen extent with no pixels up- or down-scaled. This yields 232 ppi, which would be a very nice increase in resolution for the iPad over the current 132 ppi. The iPhone's pixel count would then be exactly half of the iPad's at 960x680. The ppi would then change extremely slightly from 326 to 328 ppi. (note that iPhone ppi divided by iPad ppi: 328/232=1.414). Currently it is 960x640, so this again breaks down beautifully and provides for wonderfully simple mathematical ratios underlying all the beauty of the pixel density and practicality of scaling between device orientations and among devices.