While in the Navy in CA: 10 minutes when I lived on base, and 15 when I lived off base.
My first civilian job in OR: 6 minutes.
2nd civilian job in OR: 10 minutes. 12 with traffic.
Back home at school: 30-45 minutes depending on the weather. I hate it. People in Virginia make a conscious effort to drive worse when there's rain.
Any longer and I start using the bus. Yes, gas is cheap now, but I'd just as soon not risk my vehicle with these idiots.
I cant imagine folks who spend an hour or more every day in their car. They must be miserable by the time they hit work. An hour on the train/metro doesnt thrill me either.