Albums with sci-fi themes or mechanics -
Deltron 3030 by Del Tha Funkee Homosapien: Fantastic Rap record with one foot in cyberpunk, another in Manga.
David Bowie by Diamond Dogs: Post apocalyptic record, his best from the Ziggy Stardust period
Fragile - Yes: for the song Starship Troopers and the amazing cover art.
Land of Hunger by The Earons: for stage presence
All of GWAR's records (not at all for kids)
Flaunt it by Sigue Sigue Sputnik (and all their other albums too)
Songs with sci-fi themes or mechanics (not including those mentioned above)-
To Tame a Land by Iron Maiden: Dune in Heavy Metal form
The Prisoner by Iron Maiden: The Prisoner TV show in Heavy Metal form
Somewhere in Time by Iron Maiden: Time travel story in Heavy Metal form
Pump up the volume by M.A.R.R.S.: sci-fi heavy video
Skullcrusher Mountain by Jonathan Coulton: As featured on Escape Pod
The Final Countdown by Europe: Possibly the worst song ever recorded (Gob Bluth's theme music on Arrested Development)
Elektronik Supersonik by Zlad: Australian comedian's "Molvanian" alter ego video here
http://www.youtube.com/watch?v=lp_PIjc2ga4