When the picture cuts out, do you still have audio?
Just bought the UN55B8000 last week and am extremely pleased with the picture quality: almost. From time-to-time (sometimes a few minutes apart, but usually hours apart) the screen goes to black for less than a second and displays the Source List (HDMI1/DVI) and other data. The picture then returns to normal. I do not think this happens while watching Blue-Ray on HDMI2.
The HDMI1/DVD input is fed by a HDMI cable from a Verizon FIOS box.
I think the TV settings are pretty much the default settings that came straight out of the box.