One of the best presentations I saw at ISNIE over the weekend was by FSU-Law's Dino Falaschetti on auditor independence. The takeaway points as I understand them: first, auditor independence matters. Second, it matters so much that firms are already doing it; therefore, some of the SARBOX provisions are superfluous. Here's a link with title/abstract/author info:

Auditor Independence and Earnings Quality: Evidence for Market Discipline Vs. Sarbanes-Oxley Proscriptions

Dino Falaschetti, (FSU College of Law and Hoover Institution)
James Brown, (Montana State University)
Michael Orlando, (Economic Advisors, Inc.)

Abstract: "Does auditor independence improve earnings quality and, if so, is regulation necessary to realize such improvements? Popular characterizations of recent governance scandals answer “yes!” but lack support from scholarly investigations. This disagreement motivates our investigation of whether auditor independence affects earnings quality in ways that prior research would have missed, and what any such effect means for the efficiency-consequences of related governance regulations. 1. We relax a priori data-restrictions that ignore the potential for auditors’ dependence on consulting fees to enhance earnings quality. 2. We measure unexpected accounting fees in a more defensible manner, and develop a matching estimator to examine whether fee disclosures improve asset-pricing efficiency; and 3. We empirically evaluate the potential for governance externalities to rationalize proscriptive regulations. Our results offer some support for auditor independence improving earnings quality. Importantly, however, they also suggest that mandated fee disclosures exhausted any regulatory opportunities to improve this dimension of corporate governance, and thus speak more directly than does the literature against Sarbanes-Oxley’s proscription on jointly producing audit and non-audit services."