I think Adrian Peterson is set to take the mantle of "best RB" from LT more than Ronnie is, the last two games notwithstanding. I like Gore a lot as well, but think he is still below AD and Westbrook on that list.
I think Peterson is a special player, but much of the excitement surrounding Peterson stems from his spectacular performance last year. But when you go back and look at the period when he was out, Chester freakin' Taylor replicated his feats! When Peterson is in the game, the Vikes use Taylor differently, so he doesn't get as many yards per carry, but last year when Peterson was out... wow, that O-line is great.
I'm not saying Peterson isn't better than Chester Taylor... just that for Taylor to be GREAT behind that line... it really has to be an amazing line (and it has been in the few games I've seen).
Westbrook is a top-3 back in my book. His versatility makes him truly great.
Of the up-and-comers I'd like to see Atlanta hand the ball to Norwood some more. He's had 3 seasons, averaging 6.6 ypc his first year, 6.0 his second and he's at 6.4 this year. That's INSANE. He's only had 240 carries over those 2 and a quarter seasons, so it's hard to know for sure if he could keep the production up if he got more carries. Oh, and he's only had a single fumble in those 240 carries. That's VERY good.
One "problem" for Norwood is that the Falcons also have Michael Turner. He was basically Norwood for the Chargers (i.e. a backup getting great yards per carry on a limited work-load). Turns out (no pun intended) that Turner could transition to a full-time load just fine. He's got 5.3 yards per carry and 6 touchdowns this year.
Another interesting thing about Norwood is that he also has pretty good hands. He's still only 25, so he'll have plenty of chances - barring injury, of course.