Ansel Adams (landscapes)
You cannot dispute this guy, he's one of the fathers of photography and pioneered some very important techniques and equipment back in the day which greatly enhanced the development of photography as an art form today.
Gérard Laurenceau (square format minimalist landscapes)
He's got some of the most stunning black and white landscapes your eyes will ever see.
Rene Asmussen (emotive landscapes/portraits)
Studying Rene's photography sort of taught me how to insert a very "human" emotion into even the most desolate settings.
Ben Goosens (surrealistic digital manipulation)
His photo manipulations are top notch and super creative/emotive.
Steve McCurry (documentary)
In my mind the best documentary/travel photographer to ever hold a camera. There's a really good chance that you have seen his world famous shot of the "Afghan Girl" which a few years ago was all over the media and is said to sum up the affects of the entire Afghan war on people in one single image.
Dave Nitsche (conceptual still life, nature)
Dave's techniques in the Still Life genre have been replicated all over the world, and even though many would consider him to be one of the trend setters - you'd never hear it from his lips. You won't find more crisp photography anywhere. It's unreal. The coolest thing about him is the fact that he hates photoshop, so what you see is a result of hours of preparation and flawless exposure for each photo.
Andrzej Dragan (grunge portraits)
This man has a really cool style in portrait photography, his images tell a very poignant tale of the "human condition" and are sometimes kinda haunting.
Andy Rouse (wildlife)
Andy's my favorite wildlife photographer because he is one of those rare types that actually goes the extra mile to get the right shot. He'll camp out in sub zero temperatures for months on end to catch a polar bear cub, or wade through ponds in the Amazon covered in leeches looking for a rare Kingfisher. All the while he'll be the most happy jolly European ever. The moments he manages to capture are incredible. His books are awesome if your interested in this genre make sure you get one.
Jeremy Cowart (entertainment/portrait/music)
From the cast of Prison Break to Sting and Imogen Heap - he's shot them all.
Dave Hill (entertainment/portrait/music)
This guy destroys the HDR/Hyper Realistic portrait genre - for sure my fave. In my opinion he sets the standards in this genre, which most of us struggle to keep up with!