sigh
I can't believe that:
1) I read all 6 pages of this post;
2) it is 6 pages, so far;
3) it's over a year old;
4) I couldn't stop myself from contributing.
Let's toss out the math for a minute and discuss real-world applicability.
I've been in IT for... a while. When we started replacing CRT monitors with LCD monitors, they were 4:3 ratio, like the CRTs were. Back then, most users were still using one application at a time - in my particular case, many of the users were being transitioned from monochome terminals to PCs, so multitasking and using multiple apps at once was new anyway.
Average monitor size: 15". 17" for managers, 19" if you're showing off.
Then we went dual screen. Look, you can have a digital document on the left, and an input screen on the right! Screen prices dropped. Average user size: 17" for users, 19" for managers. Some users got to choose between dual 17" monitors or 1 19".
Then screens started going wide. 16:10 was the standard aspect ratio. They started going wide on notebooks first, in part, I believe, because it allowed the folding device to fit a more comfortable keyboard under the screen. a 4:3 ratio monitor on a notebook meant a tiny, uncomfortable keyboard. Desktop screens followed suit.
Eventually, as HDTV took off in the home and "16:9" became a commonly heard ratio (lol at that statement) it became a marketing point to tie monitors in with HDTV. At this point, monitor sizes in the lower 20s were more common, but resolutions were often still 1280x800 or similar. But tell someone that the monitor has the same "aspect ratio" as their HDTV, and it sounds improved! Voila, 16:9 gets tossed on top of "10,000:1 Contrast" and "6ms response" and all the other technical-but-really-marketing mess.
I've watched this evolution in monitors take place in the workplace. I can imagine it like a time-lapse video but over the course of 15 years. The answers to the question "which aspect ratio is better" in this thread has been all over the place, but no one really asked that question. The question was "Why aren't iMacs 16:10?" And the answer, as a few have pointed out, is "because." The industry moved to 16:9, mostly for marketing purposes, and it's worked itself into being a standard format for display manufacturers.
Which one is better? That depends. A 24" 16:10 monitor is going to be taller but not as wide as a 24" 16:9 monitor. As already pointed out, the "16" is just a part of a ratio, NOT a size measurement. To get to the 24", they have to adjust that diagonal line of measurement to get there. Increasing one decreases the other. A 24" 16:10 is NOT as wide as a 24" 16:9. I have a 20" 16:10 monitor at home, and a 20" 16:9 monitor at home. I have had them side-by-side. I can guarantee this.
Is the point to have more screen real estate? If it is, then yes, 1:1 is the goal, yet the industry has moved the opposite direction from 1:1 for the same reason the film industry did: the human visual input is by default a "wide angle" input. You see more horizontally than you do vertically.
From a productivity perspective, asking which one allows for more productivity... I think it's a highly subjective question, but I'll attempt to offer my *opinion* on it.
A *large* 16:9 monitor is a better choice when you're in a single monitor display scenario because "portrait" applications like word processors and web browsers do fit better side-by-side in 16:9 than they do in 16:10... again, so long as the monitor is of reasonable size, and its resolution is set to a reasonable default. 1280x720 is difficult to use in this way, but 1920x1080 and larger is great for having two browser screens or Word documents or Excel spreadsheets or whatever side-by-side on one screen.
A smaller screen and/or resolution benefits from a slightly taller aspect ratio because you're less likely to be opening two applications side-by-side on one screen; therefore your single application is given more vertical space. Additionally, if you're placing two smaller monitors in a dual monitor arrangement, 16:10 ratio makes sense because since you're already adding to your horizontal workspace, the vertical workspace is more valuable. BUT if you're using two larger monitors in a dual-monitor setup, 16:9 is again perfectly fine, because you have enough vertical real estate to manage a browser/application just fine, and can now essentially work as though you had 4 monitors by fitting 2x apps per monitor.
So which one is better? It all depends.
Why are the iMacs in 16:9? Again, probably because it's just what the LCD/LED market went to, so continuing the creation of 16:10 would cost more. But you could also argue that there is an assumption on Apple's part (likely backed by research) that most iMac users are using a single monitor configuration and that the screens are large enough with a large enough resolution to better benefit the user by allowing for multiple applications to be opened side-by-side without feeling as though they needed to add an extra monitor.
That is all.
