Yeah, a friend of mine found out about this when he bought one of the high end Pioneer plasma TVs to relace his 37" LCD that died. Not only does it rip up his radio gear in the room on the other side of the wall it's mounted on, but it can be heard slightly in the background when watching a movie during quiet monents. When the TV is turned off, it all goes away. A lot of it is coming through the power cord. He got a surge protector/filter for it and the audo system and it's reduced it to the point it's barely there even with headphones on the audio system, but it still is pretty bad on his HF radio and his scanners.
This has been well known ever since plasma displays came on the market. The word "plasma" says it all, high energy discharge similar to neon and fluorescent lighting or what amounts to an electric arc. The clue is in the buzz, the fundamental frequency of which is the screen refresh rate.
Don't think it's easy to get rid of, the noise radiates for considerable distance so you can easily fall victim to a neighbor's TV. In any case putting chokes on the power cord only attenuates conduction through the house wiring and into other electronics via that route but does nothing to stop the radiation from the display and set wiring.