My back-up titles are generally along the lines of "Hollywood Sasquatch" "A Yeti in Los Angeles" etc that give off more of a "quirky lit-fic" vibe than a sci-fi vibe.
As Dan says, I am enamored as hell with how sci-fi "The Thirty Mile Zone" sounds as a turn of phrase.
I grew up reading weird literary-fiction/sci-fi hybrids with heady titles like "The Stars My Destination" "Sirens of Titan" "Do Androids Dream of Electric Sheep" and so forth, I do like that kind of sweeping-weirdness hook. I think "The Once And Future King" is basically the greatest title ever written. I love the hook of "A Connecticut Yankee in King Arthur's Court", sort of the original literary-fiction in the guise of sci-fi hybrid title, I suppose I was going for that a bit.
I would be happy to change the title upon publication if suggested by a publisher or editor, I'm no unrealistic diva, I worked in film, I know that things are as much a craft as they are an art, I know that media is half-business and half-expression, I will happily be able to cope.
If someone told me "Mike, we think just naming it after a Warren Zevon song makes it most marketable" I would be like "whatever title that's true to some element of the story is fine by me if you think it will get it out to the largest audience and the money you're paying me is green".
The e-novella I put out, for example, had the working title "Fanfare For The Common Man".
My publisher said "That doesn't sound sci-fi at all" so we spitballed things until "The Undone Man" came out and sounded like a title Phil Dick or Harlan Ellison would use so we went with it.
I'm not married to titles. "A Sasquatch in The TMZ" would probably be smashing but then that teevee show would sue us probably.
He tells me the story of his life in L.A. in the Dennys on Sunset and Gower, behind that tacky Denny's green-roof facade, if they think "Desperados Under The Eaves" would sell without sounding too much like a Western (even though it is exactly a Western in a literal sense, it is a meditation on the soul of Southern California) then sure, I would go with that.
This is my spazzy rambly way of saying "Don't worry, wombles, I know that it is just the working title that makes my heart sing, I am not ideological about it".