OK, Carzeebear has given me months of grief but I prefer Twilight! As a teacher, holiday reading has to be light, easy to read, meaningless and for me, soppy. Twilight did all that. Funny is good too, I have Janet Evanovich for that. Harry Potter is too much like hard work when you are tired and grumpy. I am a romantic idiot and it took FAR too long for Harry to grow up and get a love interest! I disagree about the Tween Porn assertion by Viki as Stephanie Meyer leaves most of the details to the imagination. I don't like smutty details, which is why I didn't like the time traveller's wife.
So, there it is. For depth and thinking etc it's Harry. For brainless relaxation and a good sob, Twilight.