Two years ago I couldn't run more than 200m without feeling like I wanted to spew. I can now run 5km in 32mins and feel like I could keep going and feel refreshed. I love running - just me and the pavement. It's therapeutic.
I try to keep longer (5km) slower runs to once a week at the moment though, as it interferes with my muscle gaining goals. I also love doing full incline runs or 2% incline sprints on the treadmill though (and do that once or twice a week after weights). My max on the treadmill has been full speed for 30seconds. I have short legs, so it was quite the achievement I though, haha!