Yes, Barry Sanders @ Lions probably tops them all. Followed by...
Gale Sayers? / Bears
Erick Dickerson? / as a RAM
Marshall Faulk? / as a RAM
I agree, DaddoRam about the great Lion. I also think Emmitt Smith is a fine, strong and super successful RB. I never have liked the Boys from cowland but have no problem recognizing this guy's abilities and achivements --even while disregarding the statistics.
As posted in my first reply to this thread, there have been many RBs throught so many years in the NFL ...it's hard to go through a clear screening process. Larry Czonka, for instance, was a big, bull-runner type, very much like Earl Campbell, just running over defenders or knocking their socks off with a punishing style. Jim Taylor was in that category as well although not as big (hey,
none of the players in Taylor's era were that big -period).
And you're also right about the importance of the mental aspect /approach to the game
as a RB. Emsmith is an extremely smart player, perhaps a-l-m-o-s-t as smart as Marshall Faulk.
Almost. 
...not to mention his durability! I hope Marshall will still be helping the Rams win SBowls three, four years from now. :cool:
It is a deep challenge to succeed in the NFL. I believe it is more demanding and trying than any other sport in the USA; it takes a lot more character and stamina to play well and long in pro football regardless of the position.
Running backs, however, great RBs that is, have it particularly tough. They are not constantly -and I mean on every single play- being tortured as linemen are, true, but they're not as big. No,
great running backs must block against or into linemen, they have to take the handoff or catch a pass only to run with it through or around thick brick walls, wrestle with the persistent violence of LBs if only to gain --or loose-- a couple of yards or three, AND outspeed DBs. Got serious pain? No problem, you'll play with pain just like the rest of team.
It IS hard to choose the 'best RB ever.' Of the players that I remember and know a little of (please keep in mind that my "NFL glory days" were those of the mid-late 60's, early 70's then mid-late 80's and late 90's to present) ...in addition to the ones already mentioned by you and me and the others, these stand out in my mind as
very good, excellent, and remarkably tough

[in no particular order and with no corresponding quality label]. Please bear w/me,
• Les Josephson / RAMS
• Dick Bass / RAMS
• Tommy Mason / RAMS
• Larry Smith / RAMS
• Willie Ellison / RAMS
• Greg Bell / RAMS
• Jerome Bettis /RAMS
• Leroy Kelly /Browns
• Dan Reeves /Cowboys
• Paul Hornung /Packers
• Brian Piccolo /Bears
• Eddie George /Titans
• Marcus Allen /Raiders
• Bo Jackson /Raiders
• Rockie Bleier /Steelers
• Napoleon Kaufman /Raiders
• Ken Willard /Whiners
• Emerson Boozer /Jets
• Walt Garrison /Cowboys
• Mike Alstott /Bucs
• Tom Matte /Colts
• Bill Brown /Vikings
• Terrell Davis /Broncos
• Roy Perkins /Cowboys
All these men are extremely professional about their respective athleticism and the responsibilities towards the team they represent. Results have obviously varied

. But their example of courage and work are a real thrill; they are outstanding in their own merit even if only for the value of entertainment.
I appreciate your patience. It's just that I really enjoy this bit of 'running back history' --pun intended. For it is players like these that are among the folks who make this worldly life a little more "exciting."

Come on James!, Justin!, Marshall!, Robert!, Trung!
GO RAMS!!!