My Samsung 5084 was just delivered about 2 hours ago. I hooked it up to my PS3 and checked out Stealth on Blu Ray, Matrix & Matrix 2 on regular DVD and some pictures on my memory card. All looked AMAZING.
I then hooked it up to my Bell 9200 and turned on the game and was very underwhelmed with the PQ.
Let's get the terminology straight. Are we talking about macroblocking (compression artifact) or pixelation (due to a low/marginal signal strength). Try a cold reboot (unplug/replug) to see if it's better after that and check the signal strength if it's pixelation.