One of the advantages of reading on an ereader, no one can tell what you're reading.
I can't think of any paper books that I've actually hidden, maybe if I was reading some sort of paranormal romance (very, very rarely, and only if it's otherwise a good book), I might twinge about people seeing it.
Since I mostly read Sci-fi, modern fantasy, Lovecraftian horror, mixed with a bit of King, Koontz and others, I don't really have much reason to hide what I read.