Only 5, I can name 21 teams I would love to beat. We have a losing head to head record to Michigan, Penn state, Purdue, Ohio state, Indiana, Minnesota, Alabama, Arkansas, Stanford, Duke, Georgia tech, Houston, Mississippi, Virginia Tech, Syracuse, Washington State, USC, Florida state, Texas, Oklahoma, Pittsburg so those are my choices.
My top 5 would have to be
1) Virginia Tech
2) USC
3) Florida State
4) Alabama
5) Arkansas