BabyPiglet, Shackespere never wrote any books.
I think it really depends on your age. I know of a ton of good books that I would recommend reading, but most are for older age groups. Here is a list anyway
I listed the grades as far as readablity goes

(including analytical difficulty):
The Lord of the Flies - William Golding (8-9 grade)
To Kill a Mockingbird - Harper Lee (8-9 grade)
1984 - George Orwell (9-10 grade)
Animal Farm - George Orwell (8-11 grade)
A Separate Peace - John Knowles (9-10 grade)
The Catcher in the Rye - J.D. Salinger (9-12 grade) *My favorite*
The Turn of the Screw - Henry James (12-college) *My favorite*
The Awakening - Kate Chopin (10-12 grade)
The Shinning - Stephen King (7-9 grade)
The Lord of the Rings Trilogy - J.R.R. Tolkein (7-9 grade)
The Grapes of Wrath - John Steinbeck (9-12 grade)
Crime and Punishment - Fyodor D. *I can't pronounce the last name let alone spell it lol* (12-college)
Emma - Jane Austin (10-11 grade)
Pride and Prejudice - Jane Austin (10-11 grade)
And there are SO many more to list but I'm running out of time lol.