Sticking with games I saw in person, I was there at Williams when we beat highly rated Iowa and Indiana in the Tubby era, and there for a big win vs. Michigan against Tractor Traylor and a very talented but underachieving group.
I never got to see any big games live in the Dutcher era, although I did see a great game vs a hot shooting Purdue team in 1982 or 1983 ( I think we lost).
I don't know how big it really was, but I enjoyed the win last year in Des Moines vs. Louisville as much as any of them. Maybe it was the warm spring weather and great atmosphere outside and indside the arena, combined with the somewhat unexpected win in front of a very loud Gopher crowd. Even the Iowa people there (probably more Iowa State fans), and the Michigan State fans filing in seemed very impressed with the whole spectacle.
I do slightly recall the greatest Gopher team ever in 1977 (think they also beat Louisville- my dad had that one on the radio) that destroyed Champion Marquette and only lost 2 or 3 games total. I remember a bunch of great games with the 1982 championship team (at Iowa, Ohio State clincher), and then numerous games from the Clem's Final Four team.