pixels
@Trana:
Oh, how quaint to state 19"-20" and 21"-23", and not separate them. And then selecting the "most common candidates" in a very awkward way. Well, here's a more thorough list:
17" has 1280x1024 (5:4)
18" has 1366x768 (~16:9) - they are all 18.5" though, so sometimes counted as 19"
19" has 1280x1024 (5:4), 1440x900 and 1680x1050 (16:10)
20" has 1600x1200 (4:3), 1600:900 (16:9), 1680x1050 (16:10)
21" has 1920x1080 (16:9) - well, actually they are all 21.5", and instead often counted as 22"
22" has 1920x1080 (though actually 21.5"), 1680x1050 (16:10) - there is also a higher end 1920x1200 Eizo, but it seems to be the only one
23" has 1920x1080 (16:9) - there are 1920x1200 monitors, but haven't seen new ones introduced for a while, so might be hard to find
24" has 1920x1080 (16:9), 1920x1200 (16:10)
25" has 1920x1080 (16:9), 1920x1200 (16:10) - 16:10 are 25.5", and sometimes counted as 26"
27" has 1920x1080, 2560x1440 (16:9), 1920x1200 (16:10) - at least some of the 16:10 are 27.5", thus sometimes counted as 28"
30" has 2560x1600 (16:10)
So it would seem 22" and 27" are the only Achilles' heels for 16:10. And even that is only unless we include the 1920x1200 Eizo for 22". It's also a similar (but the opposite) situation in 27", where I think the 1920x1080 is way more common than the 2560x1440, of which there are only few higher end models.
Though I was certain I also saw somewhere a 16:9 2560x1440 in 30"...? Guess not, then. No matter, would have lost to the 2560x1600, in any case.