Let me start off by saying: Reggie Bush, Pierre Thomas, and Mike Bell.
These three have been a force to be reckoned with, they have talent, diversity, and an offensive line all on their side. I dont want to go off saying that they are the best running core in the NFL, but they have rushed for a combined 975yds so far this season, which, with the Saints reliance on the passing game, I think is impressive. They each play their role perfectly, Bush can run flats and passing routes great, and Pierre Thomas can break down defenses, as he is getting an mind-boggling 5.8yds per carry. And Mike Bell is the epitomie of a 3rd down back, as he is 6-0, 225, he has finesse, but he powers his way through the line. He is averaging a career high 4.4yds per carry this year, and he is 3rd on the depth chart!
This exciting group of half-backs are interesting to watch, and will continue to fit the Saints gameplay style perfectly until one gets injured.