Certainly the most from amongst the eight forwards. A good 8man running off the back of the scrum is a powerful attacking weapon. You effectively become an extra back.
The number 8 definitely runs the ball more than any other forward. The pick-and-go from the back of the scrum is a highly used set move in most teams. Not only this but the number 8 needs to have a huge work load in terms of the amount of carries they have, constantly running crash balls at the opposition defence. If you want to watch a world class number 8 in action, you should look up "Kieran Read", who is the All Blacks number 8, and easily the best there is at the moment.
Depending on your scrummy you might run almost every scrum. 8 man is usually the most powerful runner in the forwards, and often the one who gets the most touches.
