The New York Times discusses what judges wear in the USA:

Justice Allen, 61, a judge since 1986, certainly is no fashion divo. He described his formula for picking his shirts in the morning: whatever is clean and at the top of the drawer. When he gets to work, he searches the dozen or so ties draped over a blue chair in his office for one that matches his shirt. His lucky tie, reserved for Fridays with a light caseload, has a likeness of the Sistine Chapel ceiling. (He has about a dozen more “retired” ties in a closet.)

(Via The Seamless Web)