I listened to a nice CD of Gregorian Chant on the way home today. And arrived home much calmer. (I say my Rosary on the way into work, once I drop the kids off at school it's just about 1/2 hour from there to work if the traffic isn't impossible.)
We usually listen to bluegrass. Sometimes I'll get so involved in the fiddle or mandolin line that I'll drive right by where I'm going :-).
We also have the New Testament on CD ("The Bible Experience," new recording that came out last year) and we've been having a great time with it. It's full of personality. Our favorite so far (we've been listening to parts of Gospels and letters at random) is St. Peter, who sounds like a tobacca farmer frm over t'Marshvlle.