Wren took over the helm of Omnicom Group Inc. almost 10 years ago and has since led such stellar names as BBDO Worldwide, DDB Worldwide and TBWA Worldwide to ever-greater heights. By focusing on making their assets work harder and never forgetting that nurturing clients and building brands come first, Omnicom has become the world's largest advertising group.

The vast holding company, topping even Interpublic, WPP and Publicis in revenue, now offers global advertising and marketing services, specialty communications, interactive/digital media and media buying services.

From the beginning, Wren, who describes himself as the coach and not the pitcher, set out to foster more interdisciplinary cooperation while getting people to work together more productively. Daimler Chrysler, for one, has over 10 subsidiaries working on their business.

And he strongly endorses Omnicom University, started almost a decade ago to promote new relationships and cross-functional systems that continue to pay dividends. He credits the approach in part with helping the company continue its streak of new business wins, including landing the $60 million Bank of America account last month.

Not a man to seek out headlines, Wren prefers to keep a low profile. But with 5,000 clients in over 100 countries, and hundreds of offices, he's usually on the move. The omnipresent Wren spends much of his time traveling to various agencies, meeting with the people who work on the businesses, from the top down.

But then, he is hands-on. And he likes the challenge of figuring out what the future holds for the business. Just as he anticipated the 30-second television commercial becoming less prominent when he started his tenure at Omnicom, there are new marketing trends to consider, how to get the right media planners in place and the growing role of the Internet and mobile communications.

For a visionary, he has plenty to do.