While some may certainly be able to find a book on the list of the 50 worst books of the twentieth century that they love, there is at least one book I hate that did not make the list: Ulysses by James Joyce.
This book is often considered the greatest English language book of the twentieth century. There is certainly something to be said for the mastery of literary technique exhibited by Joyce. There is just one problem: no one actually reads this book for enjoyment, or even really reads it at all. It's just too miserable and pointless. I have not read it either; nor do I plan to. My favorite review of Ulysses gave it a grade of F x Googolplex, which has caused me much amusement since.
John C Wright stirred up the hornet's nest by calling a spade a spade, but his judgement is essentially correct. Like much modern art, Ulysses is technique unmoored from purpose, and perfected. There really is something amazing about the mastery of shape and color achieved by the fine artists of the twentieth century, but now they find they really have nothing to say. Ulysses is much the same, the pinnacle of the novel, except that it fails to do the one thing, the most important thing. Tell an interesting story.
The best book of the twentieth century is assuredly the Lord of the Rings, one that is consistently beloved and read over and over, even by people who would hate Tolkien's worldview and his purpose in writing the book if they knew what it was. However, most people do not, and simply enjoy the book on whatever level they are capable of approaching it. This is the greater accomplishment, and really, the better book.