I use a Samsung. at any size, there are the 6000, 7000 and 8000 series typically.
I went for a 7000 series as it contains a good balance os features and price. The 8000 series at the time was curved and I believe curved tv was/is such a bad idea that the manufacturers should recall them for flat panels.
with samsung you can selectively disagree to parts of the user agreement so that you can live without your tv recording you constantly for voice samples to send to a 3rd party to improve voice recognition etc. with LG (not sure how it is now) you could either agree to everything or nothing and then be unable to use much of the features of the tv if you didn't want it recording every conversation in the room.
my samsung appears to play all formats (I have to rename .mkv to .avi to get them to work over the network though) from my network file server.