I'll have to ask metrics superiority guy who is the best team UW ever beat (according to the metrics) but it very well could be that 2000 Miami team.
In the modern era SRS has Nebraska 95, UW 91 and Miami 01 as the 3 best teams.
Here is a look at Sagarin's all time ratings and the same 3 teams are the top 3 in the last 40 years.
http://www.huskermax.com/rating.html
Uncle Race probably can elaborate but I guess back in the day top teams played really tough schedules. Their SOS ratings are through the roof which is why most of the teams on the Sagarin list are pre 1975.
As far as talent and pro talent I can't imagine any team coming close to Miami in 00-01.
i'd have to look at schedules, but in terms of my dead reckoning from the 80s and part of the 90s, the Oklahoma and Nebraska teams did not play particularly hard schedules - they played in the top heavy Big 8 and basically whichever of those two won the head to head sailed into the Orange Bowl for the title. Colorado's ascendance helped, but overall it was a shit conference.
That's how it was. Okie State Had a few okay teams with Thomas and Barry Sanders. Iowa State and the Kansas schools were god awful. I remember the Huskies beating Kansas State 56-3 or something in '91. Those OK and N could just run the wishbone and option 60 times a game & never really be challenged.