We just finished netflixing our way through all five seasons of The Wire this year. It has become a bit of a joke to point out that it is the best show on television, but hey, it's really true.
For starters, by now it totally owns the crime drama genre. I'm generally a fan of Law and Order and other such shows, but at this point I mostly feel kind of embarrassed for them. Their cops look like they just came from a shampoo commercial and their robbers look like they're waiting for a call from their agent. The self-contained 40 minute plots seem cliche in comparison to The Wire's highly addictive, sprawling, season-long story arcs.
Of course, the show isn't aiming to build a better crime procedural - it's aiming to illustrate the life of an American city (Baltimore), the people who live there and the institutions they create. The core story revolves around the city's drug trade, both the dealers and the cops who try to catch them. But each season tackles a major public institution -- the unions, the school system, the media, the political machines -- and describes how, more often than not, they fail the people they aim to serve.
Very much worth the time to watch it all, IMHO.