There are actually not that many LCD panel manufacturers worldwide. Most LCD monitor companies simply package the LCD panels together with circuit boards and casings and such, and then sell the integrated product. Even more companies simply do the brand name. For example, Dell doesn't actually produce any monitors. Instead, it buys them from another company who puts the "Dell" name on the monitor for them. This isn't to detract from Dell or any other company who does that, by the way, since it's very common -- Dell makes its name in customer service, not in original manufacturing. By AU panel, you're probably referring to LCD panels made by AU Optronics, the largest LCD panel manufacturer in Taiwan (and the third largest worldwide, I think). If I remember correctly, Samsung is the largest worldwide, LG.Philips is the second largest, AU Optronics is the third largest, and Chi Mei Optoelectronics (where Amptron gets its CMV and Polyview monitors) is the fourth largest (and is the second largest in Taiwan) in terms of LCD monitors. Chi Mei is the largest in terms of LCD TV's though, so it's not a straight-up correlation across different products and technologies (and why they all say they're the largest LCD manufacturer; it's technically true, depending on the industry). Samsung and LG.Philips are based in South Korea, and AU Optronics and Chi Mei are based in Taiwan, and together they make something like 80% of all LCD panels worldwide. So there's always a sort of game going on where whenever Dell (or any other brand name company) comes out with a new monitor, to guess (or actually know) which panel it uses, since the panel specs are publicly available. Many of Dell's monitors are made by Samsung, for instance.
If you want close to natural color, it may actually involve simply loading the correct color profile. Otherwise, it's hard to really look up the panel's specs, and what its chromaticity is. Even reviews IMO don't do that great of a job of LCD color performance, since it's largely subjective and based on things such as marketing buzz about the monitor in question, brand name, room lighting, etc. The best way to see what monitor is good for you is to simply go out and see for yourself. Of course, with the above, I just complicated choosing an LCD monitor a lot more by giving you color profiles to worry about. The reason why I mention color profiles by the way is because I recently found out that some monitors (including CMV and Polyview) come with them built-in, but I was able to see them only via a Mac, and have no idea how to access built-in color profiles using a PC.
Regarding what I said earlier about response times, I forgot to mention overdrive. Without going into too much detail (you can read about it on the Chi Mei website, as well as others such as
http://www.extremetech.com/article2/0,1558,10085,00.asp for Mitsubishi's version), it allows 16.7 M color monitors to have quick response times; it also virtually eliminates the whole gray-to-gray reporting problem. The good part is that because it's just a circuitry change (and not a panel one), it shouldn't be that much more expensive. For example, I suspect (but haven't been able to confirm, so don't take my word for this) that our Polyview V17D (400 cd/m2, 450:1, 10 ms) is just simply the CMV CT-723D (400 cd/m2, 450:1, 16 ms) with overdrive circuitry instead of the regular circuit board, due to the similarity in the specs -- and it's only $10 more. So response times may soon be a thing of the past, as this kind of stuff becomes more common. I suspect (but again, haven't been able to confirm so don't take my word for it) that a lot of the "new" 8 ms and lower LCD monitors are really the same thing but with this same circuitry.
Here are the websites for these manufacturers:
Samsung
http://www.samsung.com
LG.Philips http://www.lgphilips-lcd.com/
AU Optronics
http://www.auo.com
Chi Mei Optoelectronics http://www.cmo.com.tw/cmo/english/ (its technology section has a nice overview of LCD technologies)
Chuck Hsiao
Amptron