It depends on what you do. 16:9 is better for wathing 16:9 movies. But if you read lots of text, narrower, longer columns are usually a lot more handy. We have way more vertical than horizontal scrollbars.
I prefer 16:9 or 16:10 because I have a lot of windows side-by-side most of the time. I don't have 1 file open while coding, most of the time 2 or 3, in that case a wider screen is better in my opinion.
I've got a surface and in my opinion 3:2 is actually better for multitasking. You can fit two windows vertically. So you end up having 4 windows side by side.
Because 16:9 ("shortscreens") was a ploy by manufacturers to sell a smaller screen for the same diagonal. Combined with much of the vertical dimension being eaten by the general pattern of window decoration + app taskbar + app toolbars + OS taskbar, and well, at least they're good for watching movies!
