Oh god.... uh lets see.....
Not Twilight because it's just about really, a creepy unhealthy relationships between a number of unlikeable weirdos.
So it's between LOTR and Harry Potter.
I'd give it to Harry Potter... I guess.
LOTR is just too padded. Like every single noun in that book feels like it has 5 adjectives as if he didn't want to let you imagine anything for yourself not even the condition of the grass they're walking on.
It's a really cool setting and idea and influenced a lot more then the others likely ever will, but it's downright grating to read. It's like playing a videogame that was made by someone too focused on making sure you played it the "right" way, his way and approached everything just as he did.
If I had my LOTR books on me i'd post a couple paragraphs about grass to show what i'm talking about, but I don't.
Don't think Harry Potter is anything special but it's the only series out of the three I can read without being annoyed.