I must be bored... ha! I just have to stir this up.
Your question was "which is being used most in our industry"? I'd go out on a limb and say the Apple Cinema displays. (And frankly, I don't have it in me to do the math to figure out if they're considered widescreen or not... bah!)
I'm basing this on my personal observation that out of all the photographers (amateur and pro) I've worked with, about half are Apple, half Windows. (so, by remarkably unsubstantiable estimates, maybe half are using Cinema displays, that gives you 1/4 or the market, and more market share than anything else, still.) Now, out of all the pro photography studios I've worked with, and that is a respectable number, for the record, all are using Apple, with the notable exception of some event and wedding shooters, and a goodly percentage of those are using Cinema displays. Please note, the "I've worked with..."
(I can just hear the responses to this... but keep in mind, since 1998 I've been working with commercial photographers as a retailer of high-end digital systems, a color and workflow consultant and an IT/systems consultant. This is based on seeing the inside of almost every major studio in New England, and quite a few outside of the Northeast. I have no drum to beat here, I work with both Apple and Win, and my joke is I hate them both. )
Although some do invest in the more color-accurate displays like Lacie, Eizo, etc, a remarkable number of studios use the basic Cinema display. My experience, after calibrating literally hundreds now, is that although they do not have the color controls the "big boys" have, they are very accurate, and very consistent, especially considering the price. The 23" is the weakest link in that statement, just to keep me honest...
What I see is that commercial shooters are much more likely to go for the 30" Cinema display than a 21" color accurate display for the same money. The reasons are always: It's more impressive to the client, and easier to show them the images during the shoot. It's more efficient, they can work faster with the added real estate. And finally, the color is consistent enough to give the prepress guys what they need (who, by the way, are usually investing in the more expensive, color accurate dispalys.)
I honestly don't see how aspect ratio plays into the decision at all... I truly see it as just a marketing ploy by the LCD guys, trying to sell consumers displays to watch movies on.
Again, before you jump on my butt, this is my observation based on experience in commercial, professional photography, not my opinion... (which is, if you're interested, that you need at least one color accurate display in a studio if you're doing post work on site, and the aspect ratio doesn't matter), and I'm just trying to address the question you asked.
( -ducks and runs- )