There's the obvious ones: Beverly Hills Cop, Lethal Weapon and of course Kindergarten Cop.
Then there's stuff like The Departed, Training Day, Assault on Precinct 13 (original and remake)
Then on the more detective side: The Silence of the Lambs, Se7en, Zodiac, The Wicker Man, Mystic River, L.A. Confidental, Mr. Brooks, Heat, The Untouchables, In the Heat of the Night, Surveillance, Out of Sight, Narc
And a couple newer ones I really liked where The Guard and End of Watch and Prisoners from last year. Oh and 21 Jump Street was fun, of course.
Yeah... didn't realize how many great cop movies there were that I really like.
Although some might not be typical cop movies, but they're all in that filter on a site I use.