The only book that I've ever not liked while reading it was Dracula. I guess I expected so much more from it, but I was bored to death (seriously, I only had to read a page or two before it knocked me to sleep).
To Kill a Mockingbird was pretty cool. I didn't mind any of the others, but wasn't really infatuated with them either.
Of course, at the time, my friends and I just said they sucked and made fun of them (like when Lenny sees the giant rabbit or when he tossed the puppy in Of Mice and Men).
I enjoyed the books I read for enjoyment much better, but that was the reason I read them, not because I had to for school.