SEC Football is in it's own category. I've never been to a game, but have been in the cities before/after games. It's on a different level.
For basketball, Indiana is on it's own level. I went to the IU/MU game a few years back and was extremely impressed with how hardcore they are (pre-game, during the game, and post-game). I've been to Mackey, Hinkle, Rupp, etc. IU fans take the cake easily.