In an interview with the New York Times, creator Nic Pizzolatto (who wrote a couple episodes of The Killing) seemed prepared to respond to comparisons to other recent shows. He navigates it by explaining that, basically, it isn't really a show about cops and crime: "[I]t's no more complicated than this: that you're going to use the investigation of a crime as the sort of melted cheese in which you smuggle an investigation of the human character."
For HBO's purposes, it probably doesn't hurt that we love to gorge ourselves on melted cheese.
Taken at face value, True Detective sounds like a lot of the rest of the genre: two woefully mismatched cops with very different styles are called in to investigate what looks like an occult murder, and are drawn deep into the underbelly of some remote community (in this case, it's Louisiana's bayou). But True Detective immediately feels like something more. For one thing, the narrative takes place in two different periods of time: in 1995, when officers Hart (Harrelson) and Cohle (McConaughey) are put on the case of a murdered woman found strangled, stabbed, posed in a prayer position, and wearing a crown of thorns and deer antlers; and in the spring of 2012, when Hart and Cohle are being interviewed by officers who are looking into a similar murder, one that presumably wouldn't have been committed had the right person been locked up back in the 90s. And where has Cohle been all these years, they wonder.
The characters are well conceived, Cohle in particular, a man so tormented by loss and addiction he says he believes that human consciousness is an evolutionary aberration and that the species should commit mass suicide. Harrelson's Hart is the more conventional cop character—the family man who takes the more conventional approach to police work, though not necessarily monogamy—but doesn't feel like an archetype. The show owes a lot to its cinematographer, stylist, and location scout—the acting is remarkable, but the deeply eerie atmosphere makes me way more excited about solving this crime with Hart and Cohle.
And it isn't advisable to get too attached to Harrelson or McConaughey anyhow: the series will have new characters and a whole new cast every season.