I don't know if it's my favorite, but it deserves mentioning.
In the Heat of the Night
Adam-12
Dragnet
Hill Street Blues
Blue Bloods
Chicago PD
Cagney & Lacey
Kojak
Cannon
CHiPs
Cold Case
Criminal Minds
One of the CSIs
One of the NCISs
Hawaii 5-O
Homicide: Life on the Street
The Wire
One of the Law & Orders
Miami Vice
NYPD Blue
Other
I don't know if it's my favorite, but it deserves mentioning.
In the Heat of the Night
smurf the police.
The Wire, because of what Raistlin said. Nothing compares to it, and it's so much more than a police drama; it's social commentary.