* Classic Suit: A classic, well-tailored suit in dark colors like navy or charcoal.
* White Button-Down Shirt: A crisp white button-down shirt, often with a spread collar.
* Silk Tie: Usually a simple, solid color silk tie. He was often seen wearing burgundy, blue, or a deep purple.
* No Jacket: While he wore a suit jacket in the early days of his career, Letterman became known for often appearing without one, especially in the latter years of his shows.
It's worth noting that Letterman's style, even within these parameters, was never overly formal or flashy. He had a casual, almost rumpled look that added to his likable, relatable persona.