i have an lg and i love it. it plays hd movies off of a hard drive and so far i haven't found a single file type that it won't play. i'm sure there are some out there but i haven't got one
i also have a panasonic and it's a great tv and i would of stuck with panasonic except for their quattro gimmick they got going on. it's total bs and makes no sense since the video sources don't use a 4th color.
the color accuracy on my panasonic is pretty good eccept for reds. they tend to be in the magenta side of hues. mario's hat is never quite right
the lg on the other hand is comparable to my 17 inch macbook pro. the color accuracy is amazing, i could probably run print jobs off of it. skin tones are natural. colors are vibrant and it's thx certified. the gray scales are really accurate too - no blown out whites or details lost in shadows.
samsungs are a piece a shit. unless you buy the uber high expensive tv set from them. they do make some good panels, but they sell those to other companies. their color accuracy is shit and everything is overly contrasty - which i guess impresses games because it looks sharper. we had a bunch of samsung monitors at work (graphic design) and we just couldn't do any work on them, the color was just terrible. we finally got rid of them all. my sisters all have samsung and i've tried calibrating them and their is always something not right with them. either grays are too blue, to dark. darks are too darks one color will be the wrong hue or something. i just can't peacefully enjoy a samsung.
sonys are good but highly overpriced and are easily beat by some cheaper brands. and i don't trust sony reliability.
vizio. my parents have a vizio. it's got tons of controls to fudge with which made me hopeful at first when setting up their tv to look just right but in the end, the cheapness came through. they are getting better tho. the ones i checked most recently had really good image quality and full array led which i would highly recommend because edge lits have their issues. which btw, all the samsung tvs in my family developed awful edge light leaking over a couple of years, it is very distracting.
one thing to point out about vizio is that their anti glare coating is really bad. my mom's tv got this smear marks on it because she wiped it with a damp towel. i seen this happen before but not so easily.