My you-must-read-this list

Joan Aiken - her YA books are best
Shalom Aleichem - short stories
Anon. - the Mez series of epic legends (bleak vendettas of the most tragic kind)
Marcel Ayme - short stories, fantasy
Elizabeth Chadwick - anything recent
Chretien de Troyes
Susan Cooper - Dark is Rising series
Richmal Crompton - the William books
Avram Davidson - short stories
A Drizzle of Honey (culinary research - terribly sad)
Neil Gaiman and Terry Pratchett - Good Omens
Alan Garner - The Owl Service, Red Shift
George Gissing - my personal favourite is The Whirlpool
Nicholas Stuart Grey - YA fantasy
Barbara Hambly - A Free Man of Colour and Bride of the Rat God
Ephraim Kisch - anecdotes
Margo Lanagan - Singing my Sister Down (in Black Juice)
Harper Lee's entire corpus (To Kill a Mockingbird, To Kil a Mockingbird and To Kill a Mockingbird - if you've already read it then you are due for a re-read)
Tom Lehrer - the music, not the maths
CS Lewis - The Allegory of Love
Ursula Le Guin
Marie de France
Roberta McAvoy - especially her Black Dragon stuff
Patricia McKillip
Margaret Mahy's YA books,
George RR Martin's historical fantasy
William Mayne - YA books,
Darcy Niland - The Shiralee,
Ruth Park
Mervyn Peake - Gormenghast books
Terry Pratchett
Cordwainer Smith - entire corpus of SF
John Steinbeck - The short reign of Pippin IV
L. Sterne - Tristram Shandy
Mary Stewart -especially the first three in the Arthurian trilogy,
Tacitus and Suetonius - I most recommend these if someone tells me quite seriously that they want to start reading I Claudius
James Thurber
JRR Tolkein - Beowulf: The Monsters and the Critics, Farmer Giles of Ham: Aegidii Ahenobarbi Julii Agricole de Hammo, Domini de Domito, Aule Draconarie Comitis, Regni Minimi Regis et Basilei mira facinora et mirablis exortus, or in the vulgar tongue, The Rise and Wonderful Adventures of Farmer Giles, Lord of Tame, Count of Worminghall and King of the Little Kingdom, Sir Gawain and the Green Knight (translation), Tree and Leaf (the whole volume)
Kurt Vonnegut
TH White
John Wyndham
Alison Uttley - A Traveller in Time,
Brian Wainwright - Within the Fetterlock
HG Wells - The history of Mr Polly
Oscar Wilde - the fairytales
Diana Wynne-Jones
Jane Yolen - Briar Rose
Arnold Zable - Jewels and Ashes
Roger Zelazy
Emile Zola - especially J'accuse letter and L'assommoir