Which do you like more? The original cover or the movie cover? And the results are in! (And are surprising...)

I ran an online vote with our students on which cover they preferred of the following books, and really expected them to - for the most part - go for the movie version. But have a look at the results below - the smiley faces indicate which cover got the most votes. Mortal Instruments was the only one with a tie. I then displayed all the books mentioned - and watched both sets fly off the shelves...