NC State. I have a MS from NCSU, and I'm currently in the middle of my PhD from there. There are countless similarities between NCSU and ISU, and countless similarities between the rival schools (UNC-CHeat and Iowa).
When the Cyclones or Wolfpack aren't playing, I by default cheer on the land grant universities, or the Big 12 school for non-conference games.
Oregon is a blast to watch. I always like Boise State too.