LADANIAN TOMLINSON is the greatest running back ever!!!!! by far... and when ever Reggie Bush get his chance he will then stake claim to the throne.
.....but since we're not talking about the future i would go with Barry Sanders, easy. You have to understand this guy didn't have a line nor a fullback and he broke ankles in pile ups. If he would have played longer he would have all of the running back records....put Barry Sanders in the league when Jim Brown was playing and all those defensemen that are in the hall of fame, wouldn't be because all of their ankles would be shattered.
Jim Brown was trucking dudes when he played hell everybody back then ran over defenseman that's all they knew so throw Barry or LT or Bush any shifty back you can think of put them in that era and you'll have your greatest back ever other than that everyne has a favorite, you old farts stick with your old guys and the young studs are going to stick with the young bucks there's an argument for everyone.
My list of the greatest running................
This list is based on running, catching, blocking, stats of course, leadership
1. Walter Payton
2. Ladanian Tomlinson
3. Barry Sanders
4. Jim Brown
5. Reggie Bush LMAO!!!!!!! no seriously Emmitt Smith
6. Gayle Sayers
7. Eric Dickerson
8. Tony Dorsett
9. O.J Simpson
10. John Riggins
notables: Franco Harris, Marcus Allen, Earl Campbell, Csonka, Curtis Martin, Marshall Faulk, Thurman Thomas, Joe "The Jet" Perry, Bo Jackson, Roger Graig but yea make your on list....