My mind would say 3 miles, unfortunately my legs would only go 400 yards.
For me the beginning of my runs are very hard, and mentally I want to quite. But you have to go slow and fight thru this feeling and it will get easier. I like to run 4 miles very slow 3-5 times a week. Running harder is probably more beneficial but for me avoiding injuries and setbacks is most important. I'm not you typical jogger. I'm what you call a large Clydesdale.
Over the last couple of years I've become addicted to the sun. Yesterday I took off of work, and walked around a nice lake by my house that has a 2 mile track around the lake for walking, jogging, biking, rollerblading etc. It was 94 and sunny all day yesterday, I walked 10 miles. I was out there from 12 noon to 5 pm. It was so hot that the track was pretty much a ghost town. Me and a few others, I think I saw Jaguara or his ghost doing some strecting excercises. Sure beat seating in the office.