In this Google Webmaster video, Matt Cutts, the head of Google web spam answers the question:

Matt, Does the good guys still stand a chance? We’re a small company that hired an SEO firm that we thought was legit, but destroyed our rankings w/ spam backlinks. We’ve tried everything but nothing helps. What can a company with good intentions do?

Is there anyway to answer this question without making the person feel silly for getting himself in this situation?  Matt does his best to answer this question without being too sassy.