I'm not the biggest fan of "best of" lists ("worst" lists are more fun), nor do I feel the pundits' need to label something "the greatest" this or that of the year/all time/in the history of man, etc. But if that's what it takes to draw attention to something that's woefully underappreciated, then let the hyperbole fly!
David Simon's "The Wire" has somehow endured four seasons on HBO, thanks to critical kudos but more importantly, to an audience willing to pay for its often unrelenting bleakness and complex, some-would-say convoluted, fractured narratives--a small audience, perhaps, but the right one. But don't let the raw language and explicit drug use put you off a unique drama that's humane, blackly funny, and perversely optimistic amidst the grue and the gumshoes of modern Baltimore.
Slate's Jacob Weisberg pleads his case as to why "The Wire" is "the greatest thing ever broadcast on American television" here, and damn if he doesn't nail why you should be watching. With BitTorrent and boxed sets, you've got no excuse (hint: you can catch up with the current season four if you watch season 3 in its entirety--only 12 episodes--but if you enter this season's installments cold, you may be completely baffled!).