I have read so many books, I could not name a favourite. Right now I'm reading one called Tick Tock by Dean Koontz, which I am quite enjoying. I've read a lot of his books and enjoyed them all, particularly his Frankenstein books, Odd Thomas books, The Taking, and Watchers, which is the first one of his I ever read. Love Inspector Banks too -- Peter Robinson.
I have read Foxfire by Joyce Carol Oates more than once, though I'm not sure that necessarily defines it as a favourite. I just certainly like it.