Two Back Attack is the norm... Who's got the best?

I wouldn't consider a two-back combo to be "very good" or "great" unless both backs were at least average or above average.

1. NO - Deuce (way above average), Reggie (above average now, major potential)
2. Miami - Brown (above average), Ricky (above average to very above average)
3. Washington - Portis (way above average), Betts (above average)
4. Jax - Taylor (average), Jones-Drew (slightly above)
5. Dallas - Jones (average), Barber III (slightly above)

You could make the case for NE. Dillon is about average and Maroney is probably slightly above, as of now.

IMO, these teams don't qualify:

Chicago - Jones (average or slightly below), Benson (below average)
Houston - Not a single above average RB.
Denver - Ditto