The series spawned the catch-phrases "Trust No One" and "The Truth is Out There," and fosters a huge fan-based following to this day. No matter what the ultimate fate of the show, I feel this will always be the case as it is a legend in its own time.
In 1998 the series produced a major motion picture, "X-Files: Fight The Future" which attained considerable critical and box office success, both for non-fans and X-Philes.
Over the course of the next few years, the show would undergo several changes both by way of character growth and plot direction. One of the central mythologies of the show, Mulder's search for his sister, would finally be resolved, as well as a few turns of events involving the ever-deepening bond between Mulder and Scully. Whether they "should" or they "shouldn't" consummate their relationship has been the subject of great debate among the fan community.
The show is currently in its 9th Season. While David Duchovny did not wish to return (his involvement was limited in Season 8), Gillian Anderson still holds a starring role, though has expressed disinterest in doing futher seasons. As a result, several supplementary players have been introduced, played by [Robert Patrick]? and [Annabeth Gish]?.
When and how the show will end is uncertain, but it seems likely that the involvement of the original stars is not yet over. Both Gillian Anderson and David Duchovny have expressed interest in doing the sequel to 'Fight The Future', probably to premiere in the Fall of 2003.