i'd just like to say that i think i saw what andrewscott is talking about with respect to motion artifacts / large macroblocking.
i was in BB looking at their HD loop on the 46XBR2. I was watching the Dr. "House" segment.
every time there was a scene change, as in the camera switched between three people talking, I saw a SPLIT second of this effect. Maybe 1 or 2 frames. inbetween sorta, the image change, the screen would show large compression blocks, like a pixelated censored image. now i have no idea if that was the tv or the compression. i am leaning towards compression becasue from encoding movies myself, i know sharp frame changes are tough on compression. in any event i saw it, i had to look REAL hard for it, and it was only for a split second.
is this what you've all been seeing? (for thoes who see it)