I clicked "other" because my favourite kind is sci-fi comedy. Red Dwarf, Hitch Hiker's Guide, and Futurama are my all-time faves. Other than the humour, all three share a sense of being lost that really appeals to me. Dave Lister and Arthur Dent are two different versions of the same character, which is the last man alive lost in space. The fact that they are very different is largely down to class (Lister is obsessed with curry and lager, while Arthur is lost without a good cup of tea). Fry from Futurama channels some of Lister's goodness and stupidity, and, being stranded 1,000 years in the future, could probably relate to his predicament. And all three have bittersweet love interests that heighten the loneliness (Kochanski, Leela, Trillian/Fenchurch).
I also enjoy the kind of whimsical "sci-fi" that's really just fantasy set in space, rather than Narnia or Hogwarts or wherever you normally find fantasy. Zathura, Larklight, The Little Prince, Marvin the Martian, etc..