Well, I usually use the voice calling feature on the Windows Phone. Press and hold the Windows logo and you can say "Call << Name >>" or "Open << App >>".
This feature works through the BT headset as well. I have a Plantronics Voyager Pro. While driving I don't even have to take the phone out of my pocket, I just press and hold the Answer/End button my headset and the Voice function is activated and I use the call command.. and BOOM... the phone calls while it's still in my pocket.
Another great feature is, when I get a text message, the phone recognizes it's on BT and through my BT headset, it will state that I received a message from "Number" or Name" and asks me if I want to "Read" or "Ignore". It reads out to me, and give me an option to "Reply" or "End". If I say reply, it will ask me to say the message. The Voice to Text feature... Works pretty well when you get used to it.
Sorry if I bored you... I am too exited with my NL 920.