1. Barry Sanders
2. Walter Payton
3. Jim Brown
These are the top 3 right here, it doesn't matter where exactly you have them in the top 3...they just need to be there. There is quite a few that deserve to be the final two in the list, its basically a toss up imo. Dickerson, Simpson, Campbell, Sayers, Jackson, Faulk and Tomlinson.
I would put Sayers at 4 and Bo at 5 just because they were both freaks of nature and they didn't get to play that long....just on the pure potential they had they made my top 5.