This is an excellent question. I would vote for Iowa, but after losing another running back last week, they're in a lot of trouble. Vandenburg will probably be the best throwing quarterback in the conference, but he's without McNutt this year too. I would vote for Penn State, but I think most people expect them to have an OK season this year.
Ohio State becomes the next best option. They return a quarterback who, when healthy, is a pretty good player. They've retained playmakers on the offensive and defensive side of the ball, and they've got Urban Meyer. Whether Meyer will be successful or not is still hazy, but he's the only coach in the B1G right now that's won a MNC, so that's got to count for a little something.