Well, my only favourite book that people here might recognise (I read most of the others in german and thus don't know the english title) is 'Blindness', and I loved it, especially the unusual (though difficult) style that actually gave me the impression to be blind myself while reading. Anyone who read this as well will know what I'm talking about.
Haven't found too many books I feel like reading in english in the last months though, but I'm sure I'll find something I like when more people post here.
One of the books I'm reading right now, "Demian", is very promising and could be another favourite book.
Also, I started reading a biography of Nietzsche, a series of letters by schopenhauer as well as some books about psychology, especially on the topic of dreams as it fascinates me. Those are great, though hard to read as well (especially the letters by schopenhauer)
Though I don't want to appear like I only read tha kind of books xD I read alot of books only made for entertainment as well, only that I don't concider those my favourites.
Will post again tomorrow when it isn't after midnight.