Ugh. We have four cars, two drivers.
We live on a farm, so one of the trucks is an un-plated farm truck for plowing, trucking manure, and hauling stuff.
The other truck is my husband's. He is using it to commute to work. It is a toyota, though, so the mileage is pretty good. And when I change jobs, he'll be commuting with the Prius. But we will still need a pickup for going to get hay, hauling the trailer, or when he needs a truck for his job.
We have a minivan for transporting animals.
And we have the Prius, which I currently use to commute (but come December, will be biking to the bus to commute.)
One of our problems is that I have joint custody of my daughter, which means that some nights, I have her, some I don't. This requires transportation and, as another poster mentioned, she is not interested in biking the eleven hilly and not bike-friendly miles to her Dad's. She'll be sixteen in two years, and very likely we will have to get her some economical beater in order for her to go back and forth between houses.
This also affects my bike commute, because I have to make sure on my days with her that she gets to the bus, which is five miles from our house. I have thought it up, down, sideways and backwards... I thought of getting a tandum but then, how do I get it home at night if she goes to her Dad's that night? So I am resigned to the fact that, for now, the days I have her, I will have to drive to the bus. At least it is shorter to the bus than it is to my current job... I will be saving some gas and carbon points.