The ability to select which audio output device it outputs to.
Supposedly, Windows 7 has it but requires applications to be aware of it.
http://msdn.microsoft.com/en-us/library ... 85%29.aspx
(and supposedly, Windows Media Player supports it though I can't bring myself to even launch it.)
Of course, only works if you have multiple sound devices (if you have a bluetooth adapter and bluetooth capable speakers, it comes up as a "bluetooth stereo" device).
For those who don't understand, I just want to be able to have VLC play sounds on my bluetooth capable speakers (it's a clock-radio with bluetooth syncing) so I can stream internet radio on it) yet still be able to do everything else with headphones.
I'm sure there are instances where people what to play a movie on their HDMI displays and select a specific display and specific audio device to output to.