Finest

New Yorker's have grown accustomed to a litany of superlatives regarding many facets of human endeavor and achievement in this city. Best, largest, first, oldest, most ... 
Conveniently, the NYPD fits right in - the New York Police Department is not only the largest in the United States, it was the first - established in 1845. And here in today's photo, we have, appropriately, the 1st precinct, located in lower Manhattan at at 16 Ericsson Place at Varick Street. This precinct is also one of the few that stables horses - see my article with photos here.
The city has used various nicknames for groups of uniformed city employees - New York has the Finest (police), Bravest (fire), Strongest (sanitation), and Boldest (corrections) and recently a marketing campaign to recruit teachers has asked to "Join New York's Brightest." The use of Finest for the NYPD, is, according to etymologist Barry Popik, probably the oldest:

Several sources claim that it was coined by police chief George W. Matsell. "Finest" probably started life as "Best" and probably dates from 1874. The comedian Gus Williams starred in the play One of the Finest in the early 1880s. I believe that "the finest police in the world" is meant to be a similar phrase to Civil War General Joseph Hooker's "finest army on the planet."

Popik gives many other references from this time period - you can read them at his site here, along with origins of Bravest, Strongest, Boldest and their earliest usage in regards to uniformed workers. These terms, including New York's Finest, are primarily media terms. Citizens rarely use these words, most often just referring to the police as the "cops."
Of course, whether or not the NYPD lives up to its nickname given them 135 years ago, is another question. Certainly the NYPD has had its share of scandals, perhaps to be expected allowing for such a large police force, large city population, the number of crimes committed and the violent nature of America.
I am sure working in an environment where an individual is constantly exposed to the dark side has an impact. Also, being in situations which are potentially life threatening means serious judgements have to be made, often with only a moment to make them and of course some of these decisions will be flawed.
And of course there are always the bad apples in the barrel that give others a bad name - many of these are the raison d'être behind the big public scandals of New York's Finest ...

TIDBIT: When registering the domain name for this website, New York Daily Photo, I noticed that the initials NYDP used the same four letters as the NYPD. This would make a very short and simple website address. Excited by the prospect of using NYDP.com, a little research turned up the fact that it was, of course, aready taken :(