Google Insights for Search is another great tool that can help marketers plan and refine their campaigns. It lets you compare search volume patterns by category and geography over time. You can explore seasonality, geographic, and product trends. As an example, by analyzing geographic trends over time of search patterns for your brand and your category, you might identify a high ROI metropolitan area to focus a concerted marketing effort.
I would be surprised if any brand manager who spent a half hour or so with this tool didn't find at least one useful insight - about yourself or your competition. Or, at a minimum, it should raise some interesting questions.