According to this website, the highest paying adwords are:

• mesothelioma treatment options
• mesothelioma risk
• personal injury lawyer michigan
• michigan personal injury attorney
• student loans consolidation
• car accident attorney los angeles
• mesothelioma survival rate
• treatment of mesothelioma
• online car insurance quotes
• arizona dui lawyer
• mesothelioma article
• new york mesothelioma

In fact, the word "mesothelioma", a kind of cancer often caused by asbestos (which means you have a potentially lucrative lawsuit in your near future) dominates the list. Other popular words are "insurance", "lawyer", "attorney" and "quotes". Anyone doubting the economic impact of litigation on the American economy?

(And yes, it will be interesting to see what this posting does to my Adsense account. My hypothesis: Nothing at all.)