UNSW students were introduced to some well-hatted mathematicians as part of their first year mathematics course. These students were then asked a difficult question: "Which mathematician has the best hat?"

Descartes
Euler Descartes Archimedes Fibonacci Berkeley Gauss

The results are in, and in addition to being the world's greatest mathematician, the students have decided that Leonhard Euler also has the best hat. He won easily with almost twice as many votes as Descartes.

Results from Mathematics 1A

Some students argued that the vote was biased, since Euler and Fibonacci are wearing very similar hats. Nevertheless, even with some degree of error, Euler is convincingly the winner.

Descartes and Archimedes came close, with a mere 16 votes between them. Again, this result was contested by pro-Cartesian students who argued that the vote was unfair since Descartes is not actually wearing his hat, and that it is only partially visible.

Bishop Berkeley, who would clearly turn some heads in Paris or New York while donning his sweet hat, failed to resonate with the students. Perhaps on account of his objections to infinitesimal Calculus?!
Gauss appears to be wearing the same hat, but according to the voters it looks better on Berkeley.