Personally most of my runs are fasted runs but it's not because of any of the potential benefits, it's because I want to get out and get it done first thing in the morning before my brain wakes up enough to start giving me excuses about why I shouldn't lace up my Brooks that day! The usual plan is to be dressed and out the door within 30 minutes of getting out of bed but occasionally the time will be stretched out to 2 hours. Part of the marathon training is teaching my body to be able to handle eating a small amount before the long runs and what will work the best (still a work in progress for the latter).
Not the recommended pre-run breakfast!
I'm always curious about other people's routines though, do you eat before you run or are you a fan of fasted running as well?