I had been very happy with my LG570 which was connected to a new Sony 60EX500 LCD. I decided, however, to exchange the Sony for an LG 60PK750 plasma, a FANTASTIC set, by the way. When I connected the 570 to the LG TV and played a disc, the picture did not look right. It was as if the brightness control on the TV had been turned up too high, causing the black level to look a little washed out.
I went through all of the settings on both the BD player and the TV. Everything was set the way it should be. The only way that I could get the picture to look right was to put the TV in to one specific picture mode, "standard". I really liked and wanted to use the THX picture mode, however.
So, I reluctantly returned the LG Blu-ray player and purchased a Sony 460. There is no problem with the picture now. Its strange that the LG + LG combination caused a problem but the LG + Sony combo did not.