Unfortunately, no one (who is a College Football fan) can answer this unbiased. But I will give it a shot in my experience. All universities have that one group of fans that just doesn't represent the school well. So I'm not basing it off of them. The following answers reflect the majority of the fans, not just that one embarrassing group.
Texas A&M - If you have gone to an Aggie game, or ever meet an Aggie fan/student you understand exactly what I'm saying. This cult-like atmosphere of pride can be intimidating, but it is nothing to be afraid of. However, it is uncomfortable to be around an Aggie fan all the time. They tend to either be A) Dumb or B) Overly and undeservingly aggressive in situations that don't call for it. They also try to make everything about Texas A&M and in their eyes (and this is from an Aggie mouth directly) "The world revolves around A&M".
TCU - In my experience, some of the worst fans ever. TCU does not make an effort to encourage their fans to educate themselves before a game. TCU will go 12-0 in a season and the student fans will have no idea what that means or how they got there. They attend the university, go to games and support their team but, due to TCU's notoriously weak schedule (Mountain West Conference) they rank high and fall hard in a bowl game when they play someone that actually has talent.
Here's TCU's bowl game results from the past 10 years. Let's see how your "unbiased opinion" of TCU and how they tend to "fall hard" in bowl games stacks up against the facts:
2010 Rose Bowl: TCU 21 - Wisconsin 19
2009 Fiesta Bowl: Boise St. 17 - TCU 10
2008 Poinsettia Bowl: TCU 17 - Boise St. 16
2007 Texas Bowl: TCU 20 - Houston 13
2006 Poinsettia Bowl: TCU 37 - Northern Illinois 7
2005 Houston Bowl: TCU 27 - Iowa St. 24
2004 No Bowl
2003 Fort Worth Bowl: Boise St. 34 - TCU 31
2002 Liberty Bowl: TCU 17 - Colorado St. 3
2001 Gallery Furniture Bowl: Texas A&M 28 - TCU 9
liverpool fans
Army is the worst college football team!
== == Steaua Bucharest is the football team in Romania with the worst fans.
4
That is debatable. Michigan has had the most fans in a stadium in a game, and there are fans growing everyday.
northwestern
notre dame
Michigan
Georgia tech 222 Cumberland 0!!! worst whipping ever in college football
College football was the venue through which American football first gained popularity in the United States. College football remains extremely popular today among students, alumni, and other fans of the sport.
the duke blue devils
it was the italy