Based on a discussion on another forum, I've compiled a list of great photographers (subjective) that I think the community will enjoy. It has been added to over time with reader suggestions as well.
Some of them are NSFW(not safe for work), so please bear that in mind if you decide to research them. Let me know if you find ones that are and we can add NSFW to them.
I invite one and all to investigate them and add ones I may have missed or you think we should all have a look at.
Please know that if I do not include someone, that is not a slight on them or their work - I just don't know them all! 
Please feel free to add photographers you think we should give a look into!
So here starts the list - in no particular order:
Jay Maisel
Street Photographer out of NYC
http://www.jaymaisel.com
David Hobby
Off camera flash guru and photojournalist for 20 years in the Baltimore MD area
http://www.strobist.com
Joe McNally
Worked for such publications as Time, Life, National Geographic, Sports Illustrated and now does freelance work, specializing in off camera flash.
http://www.joemcnally.com
Fan Ho
Street Photographer in Hong Kong
http://www.modernbook.com/fanho/images.htm
Richard Avedon
Fashion
http://www.richardavedon.com
Margaret Bourke White
Life Magazine
http://life.time.com/margaret-bourke-white/
Helmut Newton
Evocative, erotic portraiture
http://www.helmutnewton.com/
http://pinterest.com/search/pins/?q=helmut%20newton
Brassai
Street - Night Time of Paris
http://www.atgetphotography.com/The-Photographers/BRASSAI.html
Robert Capa
Photojournalist, war photographer, Magnum
http://www.magnumphotos.com/C.aspx?VP3=CMS3&VF=MAGO31_10_VForm&ERID=24KL535353
Henri Cartier-Bression
Street
http://www.henricartierbresson.org/hcb/home_en.htm
Alfred Eisenstaedt
Journalism/portraiture
http://life.time.com/alfred-eisenstaedt/
Ed van der Elsken
street photography/film maker
http://www.edvanderelsken.nl/index.php?page=home&language=en
Walker Evans
Documented the great depression
http://www.masters-of-photography.com/E/evans/evans.html
Philippe Halsman
Surrealist/photo manipulation
http://philippehalsman.com/
Annie Leibowitz
photojournalist for Rolling Stone/portrait
http://pinterest.com/CLIOawards/the-annie-leibovitz-portfolio/
Horst P Horst
Fashion/portraits
http://www.horstphorst.com/
Yousuf Karsh
Portraiture
http://www.karsh.org/
Dorothea Lange
FSA/great depression photographer
https://www.google.com/search?q=dorothea+lange+photos&sa=X&tbm=isch&tbo=u&source=univ&ei=cIwJUoS2OeTYyQHwpIG4AQ&ved=0CC0QsAQ&biw=1680&bih=929
Arnold Newman
Environmental portraiture
http://www.arnoldnewmanarchive.com/
Gordon Parks
portrait/journalism
http://www.gordonparksfoundation.org/
Steve McCurry
photojournalism/portraiture
http://stevemccurry.com/
Irving Penn
Fashion
http://irvingpenn.org/
Man Ray
Dada/Surrealist
http://www.manraytrust.com/
W. Eugene Smith
photojournalist
http://life.time.com/w-eugene-smith/
Edward Steichen
photojournalist
http://pinterest.com/search/pins/?q=edward%20steichen
Alfred Steiglitz
photojournalism/portraiture
http://pinterest.com/search/pins/?q=alfred%20steiglitz
Edward Weston
Still Life/portraits/nudes
http://www.edward-weston.com/
http://pinterest.com/search/pins/?q=edward%20weston
Diane Arbus
portraiture
http://diane-arbus-photography.com/
Garry Winogrand
Street
http://www.atgetphotography.com/The-Photographers/Garry-Winogrand.html
Weegee
Street/photojournalism
http://www.weegee.org/
Mario Testino
Fashion
http://www.mariotestino.com/
Moose Peterson
Nature
http://www.moosepeterson.com/blog/
Frans Lanting
Nature
http://www.lanting.com/
George Hurrell
portraiture for "old Hollywood"
http://georgehurrell.com/
Vivian Maier
Street
http://www.vivianmaier.com
Martin Parr
Magnum
http://www.martinparr.com
William Eggleston
Street/portraiture
http://www.egglestontrust.com
Jerry Uelsmann
photo manipulations/surreal
http://www.uelsmann.net/
Dave Hill
Commercial
http://www.davehillphoto.com/
Sebastiao Salgado
social commentary/photojournalist
http://blog.ted.com/2013/05/01/sebastiao-salgado-a-gallery-of-spectacular-photographs/
Mary Ellen Mark
Street Photography and Celebrity Portraiture
http://www.maryellenmark.com/index.html
Andre Kertesz
Street and Still Life Photography - Oddities - Some images NSFW
http://www.atgetphotography.com/The-Photographers/Andre-Kertesz.html
Elliot Erwitt
Documentary and ironic photography
http://www.elliotterwitt.com/lang/index.html
Nick Brandt
Nature Photographer
http://www.nickbrandt.com/index.cfm
Sally Mann
Immediate FamilyPhotographer PLUS
http://en.wikipedia.org/wiki/Sally_Mann
William Klien
Ironic photojournalism and fashion photography
http://en.wikipedia.org/wiki/William_Klein_%28photographer%29
Brian Duffy
Fashion and Portrait photography
http://www.duffyphotographer.com/
Paul Trevor
street
http://www.paultrevor.com/
Magnum Photographers
Various
<a href="http://www.magnumphotos.com/C.aspx?VP3=CMS3&VF=MAGO31_14
Robert Doisneau
Various
http://www.robertdoisneau.com
Duane Michals
Various
http://en.wikipedia.org/wiki/Duane_Michals
James Natchway
Various
http://www.jamesnachtwey.com/
Wynn Bullock
Nature, still life, nudes - NSFW
http://www.wynnbullockphotography.com/
Kyoichi Sawada
War photography Vietnam
http://www.archive.worldpressphoto.org/search/layout/result/indeling/detailwpp/form/wpp/q/ishoofdafbeelding/true/trefwoord/year/1966"
Richard Mosse
War photography/Photojournalism
http://www.richardmosse.com/
Jim Marshall
Iconic Music Photographer
http://www.jimmarshallphotographyllc.com/
Lynsey Addario
Photojournalist/War Photographer
http://www.lynseyaddario.com/
Louis Daguerre
Patented The Daguerrotype/Photographer
http://en.wikipedia.org/wiki/Louis_Daguerre
Henry Fox Talbot
Forefather of the modern positive/negative process
http://en.wikipedia.org/wiki/Henry_Fox_Talbot
Mathew Brady
Portraits/Civil War Photographer
http://www.mathewbrady.com/index.htm
Paul Strand
Landscape/Portrait
http://www.getty.edu/art/collection/artists/1863/paul-strand-american-1890-1976/
Jacob Holdt
Documentary
http://www.american-pictures.com/gallery/
Robert Adams
Landscape
http://fraenkelgallery.com/artists/robert-adams
Steven Shore
Landscape
http://stephenshore.net/
John Blakemore
Landscape/Still Life
http://www.libraryofbirmingham.com/johnblakemore
Lee Friedlander
Urban/Social Landscape
http://fraenkelgallery.com/artists/lee-friedlander
Daido Moriyama
Street/Photojournalism
http://www.moriyamadaido.com/english/
Long Than
Street/Fine Art/Black and White
http://www.longthanhart.com/
Imogen Cunningham
Portraits/Still Life
http://www.imogencunningham.com/
Max Dupain
Modernist Photographer
http://www.maxdupain.com.au/
Don McCullin
War Photographer
http://www.contactpressimages.com/photographers/mccullin/mccullin_bio.html
Gregory Heisler
Portrait
http://www.gregoryheisler.com/
Barbara Kasten
Abstract Photography
http://barbarakasten.net/