Police-Themed Movie Series

For the sake of thrills, drama or comic relief, many serial police-themed movies (at least three movies) became instant classics that never let their audience down... although some of them showed some signs of faltering down near the end. So, in the name of the law, you're not under arrest but you have the right to remain silent while answering the following question:

Which of these cinematic police-themed series is your favorite?

After voting, you might discuss the list here