What are the NCAA Football Bowl Rankings?

Obviously the BCS championship game is between the 1 and 2, but what about the next BCS bowls: Rose, Sugar, Fiesta, Orange? Which is the second best, third best, etc. And then, which bowl is the next prestigious to be invited to? I know some bowls have traditions like the Sugar is supposed to be between the SEC and the Big 12 I think? But, surely there is some ranking system making each bowl game more or less respectable?