I work in the creative department at an advertising agency. Most of my coworkers wear t-shirts or polos and jeans. I wear jackets and trousers, and more than half of the time sport a knit or grenadine tie. At first some of my coworkers were worried I was a spy from the Accounts department, but now it's viewed as a positive (I think) quirk and an extension of my creativity.
The Creative Director also wears almost exclusively bespoke clothing, which means I'm not outdressing my boss's boss.