Orson Welles' Touch of Evil opens with this audacious continuous tracking shot that has been dissected by every film school student in the past 50 years. It is three minutes of remarkable film and is accentuated by the Harry Mancini score that brings it to life.
Mancini discusses his approach at length at wellesnet
"Orson Welles had a perception of everything in the film, including the music. He knew. He truly understood film scoring. And since he was making a grimly realistic film, I think he reasoned that even the music had to be rooted in reality. And that meant it all had to come from the story itself; it would have to be source cues."