I think this is the year they really want it to happen. If Auburn loses, with all their clouds swirling around, I think it's Oregon vs. TCU. If Boise was still undefeated, I think they'd be there for sure. Many of the paper pushing media saw the Fiesta Bowl as a playoff last year for the top non-AQ spot, but all know TCU is the better of the two. People just want to see it once and for all.
Me personally I'd like to see Auburn vs. TCU from a matchup standpoint (non-AQ vs. big strong SEC in a game that matters for both teams NOT a Sugar Bowl where the SEC team doesn't care) but I really hate Auburn too much to root for thatto happen.
But in all objectivity, Auburn probably should get in if they lose, especially if it's close. You could argue for Oklahoma '03 and Nebraska '01 but they really got beat down in their losses. BCS usually gets it right.