In my younger days, when I was more of a fanatic of H.R. Giger than I am now (although I still love his stuff) I used to think it would be cool to do up my apartment with resinous ridges like you would find in an alien hive. The rooms would have no corners (that way it would also be safe from hound of Tindalos attacks, as the diehard Lovecraftianist knows) and would be dark and eerie.
Failing that, it would be cool to have an apartment done up like the Nostromo’s interior, complete with cryogenic beds.
Third prize goes to this guy in the UK who has done his apartment up Star Trek: The Next Generation style. He’s selling it on ebay. It’s really quite something.