The late '90s saw the release of two quintessential Gen-X films, Swingers (1996) and Free Enterprise (1998). Both films center their narratives on small, tight knit, groups of friends dealing with the romantic struggles typical of Gen-X 20-somethings. In a way, they are both a kind of Generation X version of Diner, but unlike Diner, the films star members of the generation the narrative is about, a kind of Diner in real time.
Swingers is the more frequently discussed film, having a kind of Sundance indie cred, but as well as Swingers captures the feel of Gen X as society understands it, Free Enterprise captures Generation X as I experienced it. While the "youth culture" market and teen culture first emerged in the post-war rock-n-roll era, that market came into its developmental zenith with Generation X.
People who were born in the late '60s to late '70s experienced the first wave of what has been a continuing explosion of popular culture. Kids in the '40s could actually purchase every comic book published, and every fantasy/scifi novel, etc. But Generation X has been a generation both obsessed with and struggling to keep up with the expansion of popular culture. Generation X was exposed, thanks to syndication and cable television, to both new and old entertainment media. It is not uncommon to hear a Generation X member have a discussion of how much they love Alfred Hitchcock, Harold Lloyd, The Cure, Superman, G.I. Joe (the original "action figure", the smaller real action figures, and the cartoon), Beethoven, Rollerball, the O.C., and their Xbox 360. In fact, that list barely scratches the surface.
Sure, members of older — and younger — generations may discuss the same things, but the explosion and resulting obsession happened during the youth of Generation X and is as defining a characteristic as drive-ins and drag-racing were for the "American Graffiti" generation, or protests and the "Summer of '69" were for boomers. A large part of what defines a generation is shared cultural experience, and for X-ers that generally means popular culture.