I'm pretty sure the trend is to go wider. 4:3 -> 16:9 -> 256:81 is the way of the future. Just think of how many documents you could view side-by-side on that!
I made my "9:16 Narrowscreen" argument last time, so I will rotate between these and possibly other terribly jokes in the future, whenever these silly arguments come up.
Seriously, who cares. Especially on 24" or 27" screens, having +- 100 pixels of height can't possibly make that much difference.
One of my favorite things about my 27" iMac is that there is so much screen real estate that you don't actually need to run programs anywhere near full-screen. You can either have a lot of pretty backgroung poking out, or have multiple documents/appls/whatever side by side.
I used to have dual 19" 4:3 screens back in the day and I loved every minute of it, but the 16:9 27" is just so much more sensible.
16:9 or 16:10 is so trivial, I can't believe people care. On something like an 11.6" MBA I will admit that +- 60 pixels of height can make an appreciable difference. Once you start getting above 720P I would argue that it's irrelevant for 95% of everyday use.