Is it worth getting full car insurance on a used car?

My husband was washing the dishes last week, and something bad always happens when he does housework. The cops knocked on the door and asked him to come with them. It turns out that a Jeep had lost control going down the street and rammed ours into a parking sign, crushing it from both sides. Nobody was injured, but the other car lost a wheel and a neighbor called the police.

That was a lucky thing for us, because we only had basic liability on our car, which was a 1995 Subaru Legacy wagon. I had not realized this, because my husband takes care of the car (this is not a gender thing, necessarily, but more because he bought the car on his own before we got married and I rarely drive it). If the other driver had vanished, we would not have been covered at all and would have had to take a loss on the car.

My husband made his choice about the insurance coverage because he did not think the value of the car, especially as the years ticked by, merited the extra payments for comprehensive and collision, which would have covered us for theft, fire, vandalism and accidents. But I was curious to see the actual numbers, and to figure out what we should do on our replacement car, which would be worth a little more at the start.

What's the actual price difference?