If I had to pick one RB from the historical rosters of NFL history, I would have a difficult time choosing between Jim Brown, Walter Payton, and Barry Sanders. I know that some Cowgirls weenie will chime in with Smith, but the only thing he has on any of these guys is longevity, so he will not be a part of my post.

Think about it.  What are the most important attributes you want in a running back? You can look at measurables like NFL GM's do with the combine every year, but that doesn't really matter for this discussion, as all the players have their NFL body of work to stand on.  I think you need to look at both attributes that are difficult to quantify, and those that are easy to calculate.  I would choose the following categories to evaluate and choose one of these three players.

Points per touch

For every rushing attempt and every reception, how many points do I receive over the long term?  Based on their career statistics, Jim Brown will give you .29 points every time he touches the football.  Walter Payton will give you .17, and Barry Sanders will give you .19.

Touches per game

I want to know whether I'm picking a player who will be a workhorse, or a change of pace guy.  All three of the players in question are close.  Sanders 22.3 touches per game, Payton 22.8 touches per game, and Brown 22.2 touches per game

Ball Security

Barry Sanders will touch the ball 83 times for every fumble he has.  Brown will have a fumble every 50 touches, and Payton will touch the ball 46 times between fumbles

Versatility

How many different ways can I use this player?  Can he catch the ball?  All three players have nearly the same average number of receptions per game (Sanders 2.3, Payton 2.6, and Brown 2.2).  The real differentiator is that Brown scored more touchdowns receiving (20) than Payton(15) and Sanders(10).  The difference is even more stark when looking at their points per reception (Brown .46, Payton .18, and Sanders .17).  

Durability 

Brown missed 0 games in his career. Payton missed 1.  Sanders missed 6 games.

I know that this is not a conclusive study, or even a good one.  I am partial to Sanders because I remember watching him play.  I think that the numbers lead one to conclude that Brown is the obvious choice if you were having a dream team draft.  I think it's safe to say that any of these three would be incredible to have on your team, and would hands down be the best player on the field no matter who the opponent was. 

For the cowgirls, here are Emmitt's stats

.21 points per touch

21.8 touches per game

80 touches per fumble

.13 points per reception

5 missed games

Maybe he does belong, but he played behind the best o-line pro football has ever seen.