I know it's an old thread, but I'd like to know this as well...when I make a call, I'd like it to always call from my Google Voice number (so people see that number and not my cell number).
Thanks, Adam. I wish that wasn't the case, but it's good to know for sure. I can use the context menu in the phonebook or when dialing to "call using Google Voice" so it would be nice if there was an option in GV to always "call using Google Voice," to avoid the extra step.