I'm not aware of this being a common issue. Does it happen if you power on the game console first, and then the television?
When I turn on XBOX 360 (component) I get a static shhhhhhh sound and some popping. It comes and goes within seconds.I don't get this sound when my satellite (HDMI) is and/or my PS3 (HDMI) is on. Also I have disconnected my surround sound system and get the issue with just the tv speakers. I tried my spare xbox vga using the tv's PC input but still get the same static sound. I can't tell if this is something that just happened I got the tv in November and I haven't turned on my 360 since I got this tv. I have tried playing with the 360 settings and currently have the audio output set to "digital stereo"