Let the hive mind of Engadget get that for you.
"I am looking for a device that will stream sound from one source to several recipients. For example, I want to stream sound from my TV or stereo to my phone or MP3 player that has radio and Bluetooth capabilities. I have looked into radio transmitters and they seem like a decent choice, but I can't find one that uses external power (USB or from the plug) and I would want one with a transmit range of around 50 meters. Thanks!"
I read that the 360 enters the same "quite mode" is does when it plays a DVD, when playing a HD-DVD.
I'm guessing it won't be as quite as a stand alone but if your looking at that sort of setup you'd probibly get a stand alone anyway.
As for the PS3 option.... I'm in the UK, I have wait 4 months to find out how loud it'll be!