What is more important to the College Football BCS, Strength of Conference or Strength of Schedule?

It appears as if the historical strength of a conference is more important when ranking teams than the actual strength of schedule. While Florida, Alabama, and Texas come from BCS conferences, the difficulty of their schedules is questionable (as are the referee calls that have led to them remaining undefeated). Boise State defeated the PAC-10 champion. TCU defeated three top 25 teams including the Atlantic Division Champion for the ACC. Meanwhile, Florida has only one top 25 win to its credit. Texas also has only one win against teams currently in the top 25. Is it their conference or their schedule which people look at?