When in doubt, I like to go with the RB; they're generally more consistent than a WR. But leaving Calvin Johnson on the bench is tough; seems like he has a higher upside.
Thing is Denver is playing at home against the Raiders, a time that has been notoriously bad against the run for a few years now. Opponents are averaging 4.6 yards per carry, and 143 yards per game.
I think Moreno is the way I am going to go. If Matthew Stafford was playing it might be different, but Culpepper and Johnson just don't seem to have a connection.