I've no idea what the "180Hz effect" means. The only thing that comes to mind is that they might be using frame interpolation to create a "smooth"-looking motion. This would be similar to what most 120Hz LCDs offer, where they insert "new" frames in between the original source frames so that everything appears to move more smoothly and evenly. I don't know for sure if that's what this "180Hz effect" thing is, but that's my guess.
THX got into the display side of things several years ago. Their goal is to basically do for video what they have done for audio - which is to provide a testing and certification service that will specify a certain level of performance and adherence to THX standards in return for the THX logo and branding that the manufacturer can put on the device itself.
THX' video standards are essentially the same as ISF and SMPTE video standards. A THX certified display will include a THX picture mode. This is a pre-calibrated mode for a pitch black room. THX cannot know what your room lighting will be like, so they went with the only standard possible - a totally pitch black room.
So, put a THX certified display in a pitch black room. Set the picture mode to "THX" and you will have a completely calibrated display. Accurate colour, accurate gamma and correct brightness and contrast levels.
But, of course, most people do not watch in a pitch black room. So you will have to adjust the brightness, contrast and possibly the gamma settings to compensate for your room lighting.
The one thing that I really do not like at all about LG's plasmas is that they have an extremely reflective screen surface. It is essentially just a glass screen with no anti-reflective or anti-glare coating, so it's as reflective as any common window.
Colour accuracy is generally very good on LG displays. This may very well be thanks to their using the THX display certification program. LG does not deliver the same deep black levels as other plasma makers though. Pioneer's Kuros had the deepest black levels, followed closely by Panasonic's current plasmas. Samsung is a step behind Panasonic and LG is a step behind Samsung.
To be honest, whether the room is dark or bright, Panasonic's plasmas look better than LG's. In a dark room, the deeper black levels of the Panasonics are quite noticeable compared to LG. And in a bright room, the Panasonic has at least some anti-reflective qualities to their screen surface.
Pioneer is the best in all situations, but they are no longer making Kuro plasmas at all and prices are still quite a bit higher than what you said you'd be paying for this LG.
Bottom line:
if colour accuracy is you biggest priority, then this LG plasma is a pretty good choice. But black levels will not be as deep as the competition and the screen surface is extremely glossy - to the point that I would honestly find it unwatchable in even a moderately well-lit room.
The Panasonic V10 series is better than this LG in every way. The Pioneer Kuro displays are even better than that.
Panasonic's less expensive lines (such as the S1 series) actually have less accurate colour. But they retain the better black levels and the better anti-reflective screen. The G10 series is a very good compromise though, as it is also a THX certified display.
Hope that helps and best of luck!
