Power Man and Iron Fist Epic Collection, Vol. 1
I'm not recommending a collection of Luke Cage's earliest stories, which you can find in Luke Cage: Hero for Hire, Vol. 1. They're a product of their era, undercut by white writers' ham-fisted attempts at black slang. In 1972, Luke was a painfully obvious and inauthentic attempt to tap into the popularity of blaxploitation -- a genre that has its own set of issues.
Power Man and Iron Fist Epic Collection, Vol. 1, which pairs Luke up with Danny Rand, aka Iron Fist, collates comics from 1978 to1986 that won't make you roll your eyes. While both characters are products of two distinct 1970s genres, they work well as a pair. Their friendship is authentic, and their dynamic is iconic. We'll eventually see this on the small screen: Netflix plans to bring Luke and Danny together (along with Daredevil and Jessica Jones) in 2017's The Defenders.
Jessica Jones: Alias, Vol. 1
Luke's origins are so explicitly tied to blaxploitation that he can be a difficult character to modernize realistically. Thankfully, Brian Michael Bendis and Michael Gaydos' Alias drops the ostentatious costume and black slang, and radically redefines Luke as a charismatic hero, similar to Mike Colter on Jessica Jones. The relationship between Luke and Jessica, which began in this run, became as essential a factor for the character as his friendship with Danny Rand.
For the love of all that is holy, avoid the gratuitous, offensive, and downright bad Cage from 2002. Instead, pick up this early-1990s installment, which involves Luke Cage in Chicago. This run is very, very '90s -- at one point, Luke fights a villain named "Hardcore." The book's pleasures come from a willingness to move through a variety of unexpected genres: Cage goes from morally ambiguous crime-solving, where our hero seems mostly guided by a paycheck, to fantastical superhero by the end, leaving logical room for the Fantastic Four to show up.