Thelonious Monk (piano, b. 1917 - d. 1982)
Those are the words of one of the most famous, inventive and eccentric composers in jazz--Thelonious Monk.
While there are at least five jazz pianists that can be considered the benchmark (the obvious being Duke Ellington and Jelly Roll Morton) I believe Monk is one of the first artists that would be mentioned with whom to start your collection with. And for all the complexity of his music, I too would suggest Thelonious Monk as one of the first purchases for anyone just getting into jazz (other pianist would be Dave Brubeck).
The playfulness of Monk's compositions and his ability to swing from blues type ballad to uptempo bebop was nothing but sheer masterclass. It's no wonder that you see many children learning about Thelonious Monk in music classes from an early age.
Now I think its time for the adults to take notice as well. The Monk catalog is massive so I would suggest starting with two records, Brilliant Corners (OJC) which many to consider Monk at the peak of his powers. Brilliant Corners also features stellar lineup with Clark Terry, Sonny Rollins, Max Roach, Oscar Pettiford and Ernie Henry. The other release I would recommend is a compilation, The Essential Thelonious Monk (Columbia Records). This unfortunately only covers his long tenure with Columbia Records but its does contain the most familiar material including one of two of my favorite songs of all time "Well You Needn't" and "Epistrophy."
Once you've checked out these two releases you can pretty much go in any direction for your next Monk fix.
Here's some video proof of Monk's greatness.
"Epistrophy" (Live): http://www.youtube.com/watch?v=F2s6LZUdYaU