the Buddhist monk and poet Ikkyu Sojun
in the realm of art
Edvard Munch- his paintings contain a richer philosophy than most people's words.
Austin Osman Spare (whom stole a lot from other work, but whose theories on magic and art are very important to my own work).
Peter Lamborn Wilson/ Hakim Bey- if I ever embrace any modern 'ism', it's Immediatism.
two other writers whom I might characterize as having a rich philosophical bent to their work: William S. Burroughs and Henry Miller.
(PS: props to the person that mentioned Robert Anton Wilson. 'The Cosmic Trigger' is an absolutely devastating book)