I kind of notice that the Chromebook Pixel has a ratio of 1.5, which translates to 2:3. This from a screen resolution of 2560x1700. Current notebook displays have a ratio of around over 1.7, which is close to widescreen TV, this from the common 1366x768 and in some cases, like the Samsung Series 9, 1600x900. I gather the newer, widescreen resolutions were conceived for a more optimal viewing of videos, but more squarish ratios are probably more suited for web browsing or viewing book pages. Perhaps that is the reason for the Pixel's ratio.

Previously to that, our notebook screen ratio for years have been 1280x800. This translates to 1.6, which is very close to the Golden Ratio (1.618) aka the Divine Section, the Golden Mean. If you don't know what the Golden Ratio is and what place it has with our natural sense of aesthetics, here is a summary:

Golden ratio - Wikipedia, the free encyclopedia

The old notebook I am typing this now, has a 1280x800 screen, close to the Golden Ratio. I like it. For some reason, the screen is just perfect. I don't mean the brightness or the pixels, the clarity or the sharpness. There is something just inherently right and balanced about the screen proportions I don't find with newer notebooks.

I can count the number of touchscreen devices whose screens are very close to the Golden Ratio. Two, the first being the discontinued first Galaxy Note (1280x800), and the second, the currently running Nexus 10 (2560x1600).