We have a car, and as work is in the same direction for the OH and I, we go in together with the bike in the boot (so I get to work clean, dry and sweat-free) and I cycle home.
Supermarket is 5 mins walk or the same time on the bike including locking-up time. I walk unless we need heavy stuff.
The car is invaluable for getting all of us around though, as our daughter is only 4. We walk to school though. I'd like to use the car less, and have in the past not had one and just hired cars when I've needed them, but we need it too often for that to be viable now, and nor do I see it being any less viable as daughter gets older. That said, most days it only does about 6 miles.
We don't have a lot tied up in the car though - it's worth less than a lot of C2W bikes, but is reliable and can easily fit 3 bikes and 3 people inside.