Not interested if I have to say a full sentence just to turn on/off my computer.
Windows Vista/7 already has speech function where you can do basic commands like open media player, click start and so forth.
This is a cool idea, but I just don't see it being super useful. The thing is newer versions of Windows already have voice controls built in. So the "open control panel" etc. seems like a moot point. So the only new thing this is really offering is the ability to turn on your computer with voice.
Which brings me to my second point. The power saving features in newer versions of Windows make it so I (and probably most people) never even shut my system off anymore. I simply let it go to sleep. Maybe there is a "wake up" voice command?