* Mark Snow. [[http://www.youtube.com/watch?v=HQoRXhS7vlU The theme]]. Because whistling is always scary.
* The wonderful melancholy underlining the score at the end of Season 1's "Conduit", conveying the despair Mulder feels at being unable to discover what happened to his sister.
* The music that was playing during ghostly children scenes in "Closure" by Moby - it was "My Weakness," off his album PLAY. At the time of filming, PLAY was on its way to becoming a hit, mainly because Moby gave lots of shows carte blanche in using the tracks for anything (trailers for episodes of PARTY OF FIVE, incidental music for BUFFY, car ads, etc.).
* The first ''X-Files'' episode to use Moby's work was the Gillian Anderson-directed "all things," which used "The Sky Is Breaking".
* Nick Cave's "Red Right Hand" for the Mulder/Barry chase up the ski lift in "Ascension".
* Soul Coughing's "Unmarked Helicopters", which shows up in "Max".
* Mark Snow's score for "Post-Modern Prometheus" is truly magnificent.
* Cher as a favourite singer of the MonsterOfTheWeek in "Post-Modern Prometheus" was not a bad choice at all. It feels like going to a fair or disco in TheEighties or TheNineties. What's not to love?
* "Paper Hearts" has great music, somewhat light at times and with dark passages. Indeed very touching.
* Say what you will about widely disliked episode "Teso Dos Bichos" (often ranking high among the worst episodes of the series), but its score was insanely magnificent.
* 'Scully's Theme', the backing music used in season 8 during scenes where Scully is thinking about Mulder's abduction. It's hauntingly beautiful.
* The first movie has absolutely epic score. Mark Snow's expanding on the theme and the varying main titles sound divine.
* The re-mix of the theme done for the 2008 movie was awesome.
* There were two excellent [=CDs=], "Songs in the Key of X" and the soundtrack of the film.
* [[http://www.youtube.com/watch?v=5-3qSL19Yzs True Navigation]], one of the ending themes [[AlternateForeignThemeSong in the Japanese version of the series.]]
* The music from the Season 4 episode "Synchrony", partly because it sounds a little more "sci-fi" than most episodes. Appropriate considering the [[TimeTravel subject matter]].