Personally, I have to say- I dump/date people for really retarded reasons. No way in hell would I date someone who thought Ayn Rand was awesome, and let me tell you- I find this to be a completely rational decision, because anyone who thinks Ayn Rand is awesome would be completely incompatible with me altogether. Ayn Rand sucks ass. And that Judy Heiblum is right- dudes who carry around copies of "Zen and the Art of Motorcycle Maintenance" are sooooo worth avoiding. Trust me (also, let me tell you- they haven't ever actually read it.).
On the other hand, I think dudes who like Henry Miller and Dostoevsky are ridiculously sexified. But I'll also think they're pretty dreamy if they've heard Mel Brooks and Carl Reiner's "The 2000 Year Old Man" or are way into Marx Brothers or Woody Allen movies. But it's not just about "Oh, you're this way because you like these specific things"- it's also about having a similar frame of reference for conversational purposes. That's really what I think is important.
I'd write more, but my keyboard is being a pain in the ass. Oy.