Anyone have this issue? I have a 2008 Mac Pro and plugging in the headphone jack does not disable the Line Out like any other Windows machine does as well as under OS X. Also there is a high amount of hiss coming from the line out and headphone out under Windows 7 x64, but there is no hiss under OS X. Must be the ugly Windows drivers. PS here is how my playback devices look, there is no setting for headphones at all.