Taking a national perspective, as opposed to my personal opinion, I think there are two answers.
Most hated today? Alabama, and it isn't close. Every fan base and talking head (with the exceptions of Mark May and Kirk Herbstreit) have downplayed Alabama's accomplishments, reveled in our disappointments and overstated the odds of negative possibilities, beginning immediately after the UA / UTw BCSNCCG.
Historically, it's Notre Dame. Their fanbase is large and loyal. But most outside that base chafe mightily at the deference shown by talking heads, particularly those in television.
My personal experience is mixed. I have a friend who is a ND graduate, and you couldn't draw up a better person or classier fan. But in Miami, I ran into an inordinate number of loudmouth jerks, and this was from a cut of the base that could afford that sort of trip.
Everybody (yes, including Alabama) has those guys, but those choices in conduct don't happen in a vacuum, and typically preclude having that level of disposable income.