Sounds like a lot of hearsay for your rankings.
Yes, lots of hearsay, since I have been to only 9 of the 12 Big Ten Campuses to see a Football game. I guess I'll have to get to OSU, Nebraska, and Illinois soon, since I know so little about Big Ten Road trips.
About Wisconsin vs. Iowa, I think my qualifying statement, that Madison is more spread out (also implied to be larger) makes the superior quantity of entertainment less powerful. I would take it a step futher, that that the Madison experience is louder, cruder, and more drunk, regardless of the liberal orientation of the town. Having said that, I still like Madison.
The only reason Indiana is high on my list is because the compact downtown, right past the Campus gates, has a pure college dominated atmosphere on Kirkwood Ave and is fun. Iowa City, with the Ped Mall, and the campus right next to it is even better, but larger. The relaxed, post hippy, tree lined Ped Mall is unbeatable. You can put a whole bunch of Minnesotan in Dinkytown, 7 corners, or Stadium Village and it does not become the Ped Mall. The students dominate Iowa City, and they are a pretty well educated, well put together group who also know how to have some fun. The students do not dominate the MN campus or any surrounding U of M neighborhood in a similar manner.
Forget about Finkbine, Cedar Rapids, and Coralville for that matter if you want to appreciate a trip to an Iowa game,, fully. It all starts and stops with the Ped Mall, preferably the Friday night before and/or postgame.