1. Penn State (3-0, 1-0 Big Ten)
Back-and-fourth contest against Auburn tested Nittany Lions' mettle. Last week: 2
2. Iowa (3-0, 1-0)
Hawkeyes defense is allowing 10 points per game, fourth fewest in major college football. Last week: 1
3. Ohio State (2-1, 1-0)
Replacing those 10 NFL draft picks is proving to be tougher than expected for Buckeyes. Last week: 3
4. Michigan State (3-0, 1-0)
Spartans hammered Miami (Fla) 38-17, now get a visit from Nebraska. Last week: 5