In a pinch, I’ll read damn near anything… 
But I generally avoid the following:
- romance/chick-lit - I’ve never been a girly-girl, waiting to be swept off my feet by Mr. Right/Prince Charming (I just got lucky that way!)
- paranormal romance - See above, except with vampires/werewolves/etc. The Parasol Protectorate is an exception for me - the series started that way, but has become more of an adventure/thriller sort of series
- self-help - I don’t believe in “easy fixes”
- torture-porn horror - self-explanatory, I think (tho I toughed out American Psycho)
- mysteries - just doesn’t generally appeal to me
- Westerns - ditto
- politics - I avoid it in real life, why would I spend my leisure time with it?
- High fantasy - a little fey goes a long way for me…
Contemporary fiction often doesn’t appeal to me either - why would I want to read about someone whose life is just like mine? Maybe that’s why I enjoy science fiction so much…
Edited to add: I’m with AuntiePam “Novels where the focus is a disintegrating marriage/relationship or careers in decline, especially if the characters are urban sophisticates – I just can’t relate to navel gazers and angsty whiners.”