Thanks for the ping! My dog used to sit on the front passenger seat, (no, I didn't open the windows for her) but now that she is going blind, she feels much more secure in the back seat of my mini-van. I would like to get a more "dog-friendly" car, but something that I am comfortable with also.
My dog (a Keeshond, ah how I miss him) used to sit in the back but when my window was rolled down, he would hang his left front paw and head out, and growl if cars got too close. He was protecting me!