Best book you have ever read

I enjoyed Artemis Fowl and Pendragon series. but if its a single book, Im not really a bookworm so I dont have recollection over a specific one. 

It's most certainly not the best book ever written, but it's the one I come back to every few years or so to read again: Shogun by James Clavell. It engendered in me an abiding interest in Japan (and by association, Korea). 
Also The Empire Trilogy (Daughter of the Empire, Servant of the Empire and Mistress of the Empire), a fantasy trilogy by Raymond E Feist and Janny Wurts. Wonderful series of books, again I have read these a few times. An alien world, suspiciously similar to feudal Japan, except with magic and other sentient races.

This thread shows that people with various tastes in literature from Harry Potter to Kafka can enjoy Korean dramas.

The Book Thief by Marcus Zusak
Baudolino by Umberto Eco
Shiver by Nikki Gemmell

When I was a kid I enjoyed:
Sarah's Nest by Harry Gilbert
The Magicians of Caprona by Diana Wynne Jones 

Of the top of my head the fae Chronicles series by Amelia hutchins was the BOMB! :):):)

All of Neil Gaiman's books tbh with The Sandman being, personally, a graphic and literary masterpiece. I also liked The Catcher In The Rye by J.D.Salinger and The Night Circus by Erin Morgenstern. These, among many others, are my favorites that I have reread.

If we talk about childhood favorites then it's definitely Harry Potter, A Series of Unfortunate Events, The Little Prince, Alice in Wonderland, Matilda and The Brothers Grimm Tales (^v^)

The Outsiders by S.E. Hinton

The Hobbit and Lord of the Rings
The Sherlock Holmes series
Anything by Edgar Allan Poe
Good Omens by Neil Gaiman and Terry Pratchett (as well as anything else by either of them)
The Princess Bride by S. Morgenstern William Goldman
The Mirror of Her Dreams and A Man Rides Through (duology) by Stephen R. Donaldson
Sherwood and Robin and the King (duology) by Parke Godwin
Most of the novels by Elizabeth Peters/Barbara Michaels

I can't pick only one!!