Choose your poison
Keith Jackson is a USC & Michigan homer, but on air he is as unbiased as they come. He is a true professional. Maybe a little long in the tooth and a little scratchy in the voice, but he is a living legend. His voice is still somewhat more steady than NPR's Diane Rhem.
Before Brent Musburger's makeover, he used to call games with a bias for the underdog. Fans of OSU, Michigan, USC, and other schools hated him because he always "obviously rooted" for them to lose. It wasn't personal, he was just calling a lot of blowouts in the 80s and frankly enjoyed a close one.
Musburger has since done a "bias makeover." If you had told me in the late 80s that he would have called "HOLY BUCKEYE" I would have bet the ranch against it.
Trev and Mark (Dumb and Dumber) make more in 2 months than I do in a year, so I'm not gonna bust their chops too hard. Although I think they need to eliminate the inflammatory junk if they are going to take their schtick to the next level.
Griese and Herbstreit aren't so bad. They are obviously pulling for UM and OSU respectively, but they are professional on camera. Not Jackson's level of unbiasness, though.