Without a doubt it is Nebraska. I don't think Bama can be in the discussion until they quit losing home games in November. Bama has lost a home game the last two seasons and I believe that keeps them from being a really dominant dynasty. Look at the 95 Nebraska team, they killed everything in their path.
And if Alabama played as soft a schedule as the Cornhuskers, they'd be undefeated, too.
And btw - Alabama has actually lost a home game in November the past THREE seasons. Of course, they lost them to Top Ten teams, which Nebraska rarely played in November.
However - if you want to use that line of reasoning, I'm fine with it.
That means:
1) Utah is better than Florida in 2008 (look what happened when they play someone - they stink)
2) Hawaii and Kansas are better than LSU in 2007
3) Boise State is better than Florida in 2006 (sure UF played the toughest schedule in the nation, but for Pete's sake they LOST to Auburn
4) Utah is co-champ in 2004, too
5) Marshall is better than Nebraska in 1999
6) Tulane is K-State in 1998
If the argument is "well they went unbeaten and it doesn't matter who you play" then you're right. If the schedule matters, they are not even in the same solar system.