I've posted before on the importance of visualization in problem solving. Here Tom Wujec tells us how the way the brain creates meaning from images. More evidence on the importance of visualization in getting a handle on larger problems. A good visualization is critical when presenting your ideas to a group or when working together in a group where different people have different ways of thinking about a problem. Visualization techniques (like mapping or modeling) can help to get everyone aligned.
By the way, this TED site is a great place to stimulate your imagination by seeing presentations by excellent speakers on a variety of topics.