Chris Carter always wanted wanted to do a second X-Files movie, but it took years before he was finally able to. He then said he hoped to do a third, concentrating on the 2012 apocalypse, which was foretold in the final episode. Clearly that window of opportunity has past, but do you think there ever will be a third movie? Do you want one? What kind would you want? The alien myth arc like the first or a stand alone monster movie like the second?
Although I would like a third film based on the alien mythology of the series, I don't think there will be one, and I do think that window of opportunity has passed. I would have been great to have a 2012 film, but since that was missed, I'm not sure how they would really go about doing another. It would seem strange not to cover the climatic 'end of the world' revelation mentioned in the last episode.
No I do not think there will be a third one, and actually I generally find that I like the original or first mostly anyway and sequels or follow ups are generally not as good or perhaps not as "interesting" as the concept is no longer new.