About 3-4 days of the week I'll hit up the treadmill for 2 miles after a workout. Sometimes I go with the stationary bike instead for about 20 minutes.
I'd say 4-6 miles/week. Sometimes less, rarely more.
I used to do more running, but I currently don't have any easily accessible trails nearby, don't feel like destroying my joints on pavement/concrete, and can't make myself run more than 2 miles at a time on a treadmill.