Wolfgang Pauli was born on April 25th, 1900, and he was one of the brightest physicists of his generation. See also "Wolfgang Pauli" at a Western European physics blog.
His approach to physics was very sharp and sophisticated. The Pauli matrices and the exclusion principle are named after him (Nobel prize 1945 for the exclusion principle) and he has proven many things such as the spin-statistics relation and the CPT theorem. In 1949, he co-authored the Pauli-Villars regularization but of course his contributions were far more numerous, including contributions that are not published anywhere.
His encounter with David Bohm
Wolfgang Pauli didn't like sloppy thinking - and especially various kinds of mishmash of unconscious projections and science - such as the morphogenetic fields and similar primordial forms of the "New Age" garbage. If you look e.g. at this page, you can see where the famous "not even wrong" epithet comes from.
Pauli was talking to another physicist, most likely David Bohm. You may know that it's hard for me to love David Bohm because Bohm was both a communist as well as a hater of orthodox quantum mechanics. So it's not surprising I like this story. :-)
Bohm was apparently emitting a lot of philosophical preconceptions - imagine something like one of Lee Smolin's silly theories - and at one moment, he self-confidently asked "But, surely, Pauli, you don't think what I've said is completely wrong?" to which Pauli replied: "No, I think what you said is not even wrong." ;-)
Too bad that between 2001 and 2006, his nice statement has been misused exactly by the intellectual heritors of crackpots whom Pauli addressed his wise comment in the first place. I am virtually certain that if Pauli were alive today, he would be a string theorist because he always demanded as high mathematical standards from a theory as string theorists do.
I hope that in 2007, we can already say that the intellectual garbage that was trying to damage Pauli's name and misinterpret his statements is already moved to the dumping ground of the history of physics.
Pauli and God
At the 1927 Solvay Conference, Dirac spent some time criticizing religion. Because Heisenberg's attitude was rather tolerant, Pauli gave the summary. He said: "Well, I would like to point out that our friend Dirac has a religion, too. Its first commandment says that 'God does not exist and Paul Dirac is his prophet.'"
It is also a well-known story that after his death in 1958, Pauli was granted an audience with God. Pauli was allowed to ask a question. So he asked why the fine structure constant was equal to 1/137.036... God started to write equations on the blackboard and Pauli was satisfied for a while. However, he soon started to shake his head violently: "Das ist ganz falsch!" :-)