I pivot on the ball of my foot. My friend Zeke is shown here pivoting off of the heel of his supporting foot.
Zeke throws 50+ feet farther than me all the time.
What do you think?

If I am using correct form (for me) then I pivot on the balls of my feet as a natural part of the follow-through. It reduces stress on the knee and improves accuracy. The hardest part (for me) is to put down the doughnuts and get my fat ***** in shape, as it requires good leg strength and balance. DD

Check out the disc mania video on youtube where Avery talks about backhands.
Near the end he suggests pivoting off the heel then demonstrates it clearly on the video.

Amusingly however, in every drive up to that point in the video he is pivoting on the ball of his foot.

It is a very good video though. Check it out.

http://www.youtube.com/watch?v=rCs5u9ecVis

At a recent clinic, Feldberg talked about this issue and said he noticed that pros throwing for distance are really pivoting on the blades of their feet, like baseball players when they hit. I had already noticed that, in some slow motion videos of mine, the pros are really putting the pivot foot down perpendicular to the line of play and pivoting on the whole foot, and not just the toe or heel. So I think Feldberg has it right.

At a recent clinic, Feldberg talked about this issue and said he noticed that pros throwing for distance are really pivoting on the blades of their feet, like baseball players when they hit. I had already noticed that, in some slow motion videos of mine, the pros are really putting the pivot foot down perpendicular to the line of play and pivoting on the whole foot, and not just the toe or heel. So I think Feldberg has it right.
Would that be THIS clinic? http://www.youtube.com/watch?v=3sxw8ix0CYs
Double G (Garret Gurthie) is throwing at about 17:30 into the video and the subject of heel to toe comes up.
I have watched GG throw since 2005 and he is fun to watch at long drives - my favorite being at the The Spirit of the Suwannee Music Park before the course was installed.
Coincidentally Zeke, the guy pictured throwing, knows GG and that may explain why he throws off of his heel.

I will have have to concentrate my weight onto the blade of my foot with this good advice.
It will be subject to my approach in the Tee Box which I am borrowing from my old Tennis Days of the Chip & Charge; When you slice through the Ball, it involves the same sort of Shuttle Stepping to get our Bodies rotating around for the Throw.