Who Do You Think is The Most Important Living Photographer?

I am thinking of doing a TV series (maybe on PBS or maybe on the WEB or DVD) in which I interview the most important living photographers?

Please let me know who you think is important - and why. A person who has contributed to the art and craft of photography. A person from whom you want to learn how and why they photograph – and what makes them tick.

Please post your recommendations here.

Thank you very much,
Rick