Best Jazz pianist

Who's the best Jazz pianist, or your favourite.
How can there really be a "best"? Oscar Peterson? Benny Green? Bill Evans? Duke sure could swing. One I have really been enjoying lately but don't hear too much about is Ahmad Jamal. He might be my "best" when the mood strikes me. He has a different style that is certainly his and his alone.
sooo many....Bill Evans, Dave Brubeck, Marcus Roberts, Art Tatum, George Shearing, Andre Previn, Thelonius Monk, Keith Jarrett...I'll let others take it from here
There are many great jazz pianist in the world, but I'm a Kieth Jarrett aficionado.
His lack of thinking of the next note really translates to the best form of jazz for me.
Although I selected one above I agree with HiFiHarv's statement "How can there be a best" The arts are not a competition. All musicians have something to offer you. It is up to you to decide whom you like
Thelonius Monk & Keith Jarrett are at the top of my list.

Surprised McCoy Tyner hasn't been mentioned yet, but he is another great one.
It would more imformative and allow for more complete posts to ask, Who is the worst Jazz pianist? Because all the players mentioned are great, and I'm sure no one named all the ones they could have named.
Post removed 
Elizabeth, you can always be counted on to cut thru the BS and get to the right answer.

I agree about Tatum. I have his solo Masterpieces set, and I don't play them very much. After a while they all sound the same. Show off.

Peterson is not always great, but he is at least always very good. Sort of like clint eastwood in the movies.

Basie's style of playing in Jazz is sort of like B.B. King's style of playing the blues. The right note, at the right time, no more or less. You nailed it.
I should correct something I said earlier. I said the Duke could swing, but I meant the Count, as in Basie. Not that the Duke doesn't swing, just not on the piano. Hard to believe I got them mixed up.
In terms of sheer technique, it is hard to come up with someone who had more than Oscar Peterson in the jazz world. He is also one of my favorites musically, though I like Bill Evans and Monk as well.

In addition to Foster_9's list; Bobby Timmons, Sonny Clark, McCoy Tyner,Red Garland, Bud Powell, and Hank Jones.
I would like to add the following, since they were on my playlist today:

1. Les McCann(piano) & Eddie Harris (tenor sax) - 'Swiss Movement'
One of the all time great Jazz performances!! Every track a winner!! I wore out two LPs. Now have it on two CDs, just in case.

2. Randy Weston - 'Volcano Blues'

Other jazz pianists Worth a Look / Listen:
Cyrus Chestnut
Walter Davis Jr.
Marcus Roberts
My all time favourite is Gene Harris (Ray Brown Trio)and others are Keith Jarrett and Gonzalo Rubalcaba.
Many of my favorites have already been mentioned. One who was not is Ramsey Lewis. He is very underrated.
My favorite are probably Bill Evans and Oscar Peterson, depending upon my mood. I also really enjoy Keith Jarrett, Tommy Flanagan, Michel Camilo, Michael Palma, Dan Haerle, and Shelly Berg (amongst many, many others).
Another person I like (who plays in the same vein as Oscar Peterson) is Gene Harris. Some of his works are really very good - you often ask "is that Oscar P playing?"....
i like Herbie Hancock with his release of Maiden Voyage and when he was with Miles
After seeing 77jovian's mention of Dave Brubeck, I had to go give him a long listen. He gets my vote.
Emperor Joseph II said "too many notes," not Salieri. And I'd certainly argue that Mozart's "too many notes" deflates Elizabeth's argument. Anyway, Art Tatum and Buddy Powell for me.
I second bud Powell. I also really enjoy Marcus Roberts and Cyrus chestnut. One surprise - Harry connick jr can really play. Try some of his albums where he doesn't sing.
Ah, Art Tatum. Yeah I get where you're coming from Elizabeth and sometimes the arpeggio runs do go a bit over the top but that's Art. On the other hand his harmonic improvisation and the absolute effortless and ease of his playing is really astounding. I particularly enjoy his solo works where he can showcase his special talent. I really love some of his early stuff, the stride style of James Johnson and Fats Waller that has long gone out of style, he really took this up a notch or two. Oscar Peterson of more contemporary pianists is fun to listen to as well in that style. I wouldn't say he is my favorite because I have no one particular favorite, some are so original in their styles that it is too difficult to chose only one but I WOULD say without any reservation that Tatum is technically the best jazz pianist I've ever listened to.
Ahmad Jamal is absolutely a stunningly excellent pianist. He is melodic, original, fun and evocative. He tops my list... closely followed by a radically different pianist, Thelonius Monk.
Not surprised I haven't seen his name on this thread, but I am down with Sir Roland Hanna. An incredibly sensitive pianist with awesome technique. Not necessarily the best, whatever the metrics on that are, but very deserving of our recognition.
A little surprised by all of the Tatum bashing. From Wiki:

"Numerous stories exist about other musicians' respect for Tatum. Perhaps the most famous is the story about the time Tatum walked into a club where Fats Waller was playing, and Waller stepped away from the piano bench to make way for Tatum, announcing, "I only play the piano, but tonight God is in the house."[55] Fats Waller's son confirmed the statement.[56]

Charlie Parker (who helped develop bebop) was highly influenced by Tatum. When newly arrived in New York, Parker briefly worked as a dishwasher in a Manhattan restaurant where Tatum was performing and often listened to the legendary pianist. Parker once said, “I wish I could play like Tatum’s right hand!”[57]

When Oscar Peterson was still a young boy, his father played him a recording of Art Tatum performing "Tiger Rag". Once the young Peterson was finally persuaded that it was performed by a single person, Peterson was so intimidated that he did not touch the piano for weeks.[58] Interviewing Oscar Peterson in 1962, Les Tompkins asked, "Is there one musician you regard as the greatest?" Peterson replied, "I’m an Art Tatum–ite. If you speak of pianists, the most complete pianist that we have known and possibly will know, from what I’ve heard to date, is Art Tatum."[59] "Musically speaking, he was and is my musical God, and I feel honored to remain one of his humbly devoted disciples."[60]

"Here's something new .... " pianist Hank Jones remembers thinking when he first heard Art Tatum on radio in 1935, " .... they have devised this trick to make people believe that one man is playing the piano, when I know at least three people are playing."[61]

The jazz pianist and educator Kenny Barron commented, "I have every record [Tatum] ever made — and I try never to listen to them … If I did, I'd throw up my hands and give up!"[62] Jean Cocteau dubbed Tatum "a crazed Chopin." Count Basie called him the eighth wonder of the world. Dave Brubeck observed, "I don't think there's any more chance of another Tatum turning up than another Mozart."[63] Pianist Mulgrew Miller, a noted fan of Tatum, commented on personal growth by saying, "When I talk to the people I admire, they're always talking about continuous growth and development and I look at them and say, 'Well...what are YOU going to do?' But, as Harold Mabern says, 'There's always Art Tatum records around'".[64] Dizzy Gillespie said, "First you speak of Art Tatum, then take a long deep breath, and you speak of the other pianists."[65]

The pianist Teddy Wilson observed, "Maybe this will explain Art Tatum. If you put a piano in a room, just a bare piano. Then you get all the finest jazz pianists in the world and let them play in the presence of Art Tatum. Then let Art Tatum play ... everyone there will sound like an amateur."[65]"

I like Oliver Jones, Jessica Williams, Brad Mehldau, Cecil Taylor, Bobby Timmons, Wynton Kelly, Horace Parlan, Benny Green and Geri Allen.
Thanks, Jazdoc. No I'm gonna get me some Tatum.
For now I am partial to Bill Evans, Monk & Oscar. Cheers,
So many good choices as to be expected, there have been many talented pianist over the years and then factor in the multitude of styles.
I'll base mine on who I find myself listening to the most often.
Theloneous Monk, Herbie Hancock, Kenny Barron, Tommy Flanagan and the sleeper on my list Barry Harris (a pure bopper with a beautiful left hand).
I could name many more, I 'm just glad someone recorded these fabulous musicians.
It is fair to say that Monk, set the standard. Bill Evans, for me, a very close 2nd!
I love Monk. 
I love Bud Powell.
I love Claude Williamson.
I love Hampton Hawes.
I love Brubeck.
I love Art Tatum.
I love George Shearing.
I love Bill Evans.
I love Tommy Flanagan. 
I love  Phineas Newborn Jr.
I love  Ahmad Jamal.

Oscar Peterson = Blazing technique ... no soul.
Keith Jarrett = Please, stuff a rag in his mouth. 

They are all excellent and each have had they're special moments.
Steve Lawrence relayed a story about being a guest at a club in Europe with Fran Sinatra.On stage,the piano player asked Frank if there is something special he would like to hear.
His reply was Oscar Peterson but he's not here.
I'd like to add Vince Guaraldi to the already mentioned greats

Was there anyone before Monk & Ellington ?

Keep me posted & Happy Listening!
Oscar Peterson had a lot of soul , Canadian soul is just expressed in a different manner than ours .
Put another Canadian in there, Paul Bley .
Whence I  first  became really interested in jazz I was naturally  drawn to the  big and established  names. So it was a lot of Oscar Petterson, I like him. Later on I discovered Thelonious Monk. I wouldn't say Oscar lacks soul but he doesn't move me as Monk does, just an entirely deeper  level. Natural evolving process with added time, lisstening and  exposure to this wonderful genre.I respect Petterson but have  the highest admiration and love for Monk''s playing and equally for his fabulous compositions. There is a profound emotional  connection with Monk that isn't  evoked with Petterson. Purely  subjective  obviously as we're  discussing artists of enormous talent with different  appeal.