Because I am the biggest geek ever.
In ascending order...
21. The Swinetrek
Everybody now- "Pigs- in- Space!" From The Muppet Show.
Although technically a class of ship, I'm going to let that distinction slide. From former Nashville Film Festival Artistic Director Brian Gordon's favorite movie of all time, The Last Starfighter.
19. The Probe what Fucks Up Earth and Talks to Whales
From Star Trek IV: The Voyage Home.
18. The Planet Express Ship
From Futurama. Voice of Sigourney Weaver. Dark matter engines. Alcoholic robots. I'd be a fool not to (which I was, initially).
17. The Acanti
From The X-Men's Broodwar back in the late 160s. Originally, these were beautiful space-dwelling creatures, but a parasitic race known as the Brood enslaved them and turned them into living ships.
16. The Ubbo-Sathla Umbrella Cruiser
From Lifeforce. It doesn't look like too much, but three of this thing's nude crew turned London into a ravening soul-sucked bastion of madness and frothing out the face.
15. The Heart of Gold
From The Hitchhiker's Guide to The Galaxy. Because who wouldn't want an Infinite Improbability Drive?
14. Icarus II
From Sunshine. The only reason the Icarus series doesn't rank higher is because of the unfortunate tendency of everyone who crews them to die horribly.
13. The Nightflyer
From Nightflyers (moreso George R.R. Martin's book than the muffled 1987 film version, but either one will do). And it's not even so much because of the design, but rather that it comes with a telekinetic murderous ghost wired into the ship's crystalline hard drive.
12. The Millennium Falcon
11. Klingon D-7
Threatening but graceful.
09. Borg Cube
Because I had a Physics teacher tell me this was the most practically-designed spacecraft he'd ever seen.
08. The LV-426 Derelict
From Alien. Because of all the 'alien' spacecraft that the movies throw at us, this one actually looks like it could have been made by aliens. It is made according to a kind of symmetry we simply will never understand.
07. Martian War Machine
From War of the Worlds (1953 and 1988 versions). Technically, we don't see these in space, but they're alien and they fly, so why pick hairs. Graceful and deadly monsters, these.
06. Spacing Guild Heighliner
From Dune. Not much to look at, but if Norma Cenva designed it, then you better believe it has some awesomeness to lay down. It doesn't travel through space- space travels around it.
05. Voyager 6/V GER/Vejur
From Star Trek: The Motion Picture.
04. The TARDIS
From Doctor Who. Timelords know how to travel in style.
03. USS Cygnus
From The Black Hole. Simply awe-inspiring. Truly a ship to go mad in, with its majestic corridors, transport systems, and comfortingly sinister design. Truly unique.
02. USS Grissom
From Star Trek III: The Search for Spock. Still the most elegantly-designed (if horribly impractical) Federation ship in all of Star Trek history.
01. USCSS Nostromo
From Alien. A monster in space. Practically a city, except that most of what we see is a portably refinery, traveling for decades across space while processing ore to keep earth running. The most influential internal ship design in the past thirty years.