Widely hailed as one of the most stylish movies of all time, The Thomas Crown Affair (1968) stars Steve McQueen and Faye Dunaway. McQueen is a bank executive who orchestrates a bank heist and then plays cat and mouse with a beautiful insurance investigator (Dunaway). Throughout the movie McQueen exudes rugged sportiness and masculinity while wearing an array of three-piece suits with flat-front pants, along with his trademark Persol sunglasses with custom blue-tinted lenses.
Marion Maneker, in Dressing in the Dark: Lessons In Men's Style from the Movies, wrote that the "original Thomas Crown Affair ... remains one of the best movies for learning how to wear a suit and tie. Steve McQueen's pale blue shirt, royal blue tie and classic three-piece Prince of Wales suit conveys his character's old-money background and reckless thrill seeking better than any dialogue."
For sartorial inspiration, I recommend The Thomas Crown Affair.