Hear, hear on what so many of you have said already!
Our car insurance dropped by $100 a MONTH when I sold my car.
Parking is easier... we have only a driveway, so we'd either be tandem there or have one car on the street. The two-car tango is no darned fun when you're trying to get out of the house for the day, and I love not even *knowing* when our street cleaning days are. ;-)
Lately, we've fallen into a pattern where I usually drop DH off at work (it's about 3 miles away, and a pretty easy bus ride). On days when our son goes to school, we drop him off together first, then DH and I have a nice little 10 minutes where we can get into philosophical or profane discussions without interruption. ;-) What a neat little bit of time that's turned out to be! In general, I do think we see each other more because we share a car, not just a house.
Other cost savings: only need one carseat (per child)!

I like that it makes us *think* more about transportation and scheduling. I build more time in between commitments, and keep our absolute time commitments to a minimum, because the more flexible our day is, the less we have to worry about handing off the car.
In our old apartment, we had two parking spaces, and actually rented out the second space to a neighbor for a couple of months. ;-) My mom also would store her car there when she went on long trips (she has only street parking where she lives, and our place was closer to the airport anyway).