You missed the Adrian Peterson era? Bell is a really good back, but AD shits on Bell and it's not even close. We are talking about a person who has never at any point, even with the Favre team, has seen 8-9 man boxes. Put Peterson in the 80s & 90s and he may be the greatest football player (with the way penalties are called now on offensive-lines, and the game has adjusted so pass happy). His 2012 year is arguably the greatest single season in the history of the game coming off a fresh complete ACL/MCL repair.
Brown > Sanders > Dickerson > Sweetness > Smith (slot Peterson anywhere on that list I don't care). Any one of those guys could be ranked the GOAT. In his dead prime, give me AD any day, all day. Dude broke into the league and it was evident 6 games in he was a league above Tomlinson (who is a phenomenal back in his own right).
I have to remind people that, as a Cowboys fan, Zeke is a great back... but he is never going to be Peterson. (sorry music is awful).