If 1998 was a great year for the Big Ten, could it be that 1999 was the greatest year? Heisman Trophy winner? Check. All-time leading rusher in NCAA history? Check. Dominant teams at the top? Check. Big bowl wins? Check. National title. Argh. There's the one thing that the season is missing. But to recap...
Wisconsin pounded teams in their special Wisconsin way. You may remember this as the year that you heard the Badgers PA Announcer and then the crowd say "Ron Dayne" over and over and over again. He set the all-time rushing mark at home against Iowa, and he picked up a Heisman in December. Wisconsin went back to Pasadena and won their third Rose Bowl in seven seasons. No other Big Ten team has ever done that (Only USC and UCLA have from the Pac-8/10/12). Michigan and Michigan State were extremely strong, and they would combine to beat the SEC Champion and runner-up in bowls (Alabama in the Orange and Florida in the Citrus, respectively).
I haven't done the research to call 1999-2000 the greatest All-Sports year in history, but if you add champions in Men's Basketball (Michigan State with a Final Four berth for Wisconsin) and Wrestling (Iowa), you've got a good start for a case.