Anything by Charles Dickens (Great Expectations is the best)
Harry Potter series
Percy Jackson and Heroes of Olympus series
Hunger Games trilogy
Princess Bride I second, it's an amazing book. By William Goldberg. It's even better than the movie.
Shakespeare (Much Ado About Nothing, Comedy of Errors, Twelfth Night, basically any of the comedies are awesome to read, even better to see)
The Mysterious Benedict Society
The Giver by Lois Lowry
Anything by Kate DiCamillo
Anything by Wendy Mass (The Willow Falls trilogy is middle grade level but amazing adorable books)
Shannon Hale (Princess Academy, The Goose Girl)
Margaret Peterson Haddix I second
The Door Within Trilogy by Wayne Thomas Batson, and anything by him, the pirate books Isle of Swords and Isle of Fire are second best
The Pendragon Series by D.J. MacHale (ten amazing sci fi/fantasy books)
The Hitchikers Guide To The Galaxy by Douglas Adams and its four sequels
Wow, this is a long list, sorry if I bored you...