Being evangelical about genre fiction, I have a tendency to make long mental lists of 'must reads'. What follows are 35 books* that I consider essential fantasy.
I don't think the books on this list are the best - in fact I downright loathe a few of them (I'm looking at you, Tigana). However, I do feel these all reflect some aspect of the genre that I think is important to understand - if not necessarily enjoy.
I'm also a bit of a stickler on definitions of "Fantasy". I get really wound up by over-thought lists that include things like Moby Dick - that always feels like a passive-aggressive way of defending the genre. When I'm talking about "fantasy", I mean elves, talking swords, dragons & chainmail bikinis, dammit.
Here were the rules:
I divided Fantasy into four broad and incredibly subjective categories (Modern, High, Classics & Unclassifiable). Each author was only allowed one entry (although I stretched this a bit - justifiably - with Eddings, Gygax & Tolkien).
What'd I get right? Wrong? Tell me in the comments. If there's any sort of interest, I can add some vague annotations. But, right now, it seems more fun to provoke wild speculation (and hopefully some heated debate).
CLASSICS
Marion Zimmer Bradley - The Mists of Avalon
Edgar Rice Burroughs - Tarzan of the Jungle (Tarzan)
Arthur Conan Doyle - The Lost World
H.R. Haggard - King Solomon's Mines
M. John Harrison - The Pastel City (Viriconium)
Robert E. Howard - "Beyond the Black River" (Conan)
Sax Rohmer - The Insidious Doctor Fu Manchu
J.R.R. Tolkien - The Lord of the Rings (All three)
Jack Vance - Tales from the Dying Earth
T.H. White - The Sword in the Stone
HIGH FANTASY
Stephen Donaldson - Lord Foul's Bane (Thomas Convenant)
David Eddings - The Belgariad (All five of 'em)
Tracy Hickman & Margaret Weis - Dragons of Autumn Twilight (Dragonlance Chronicles)
Robert Holdstock - Mythago Wood
Guy Gavriel Key - Tigana
Ursula LeGuin - The Tombs of Atuan (Earthsea)
Fritz Leiber - Swords in the Mist (Lankhmar)
Michael Moorcock - Elric of Melnibone (Elric)
J.K. Rowling - Harry Potter & The Philosopher's Stone (Harry Potter)
Philip Pullman - Northern Lights (His Dark Materials)
MODERN FANTASY
Joe Abercrombie - The Blade Itself (The First Law Trilogy)
Terry Brooks - The Scions of Shannara (The Heritage of Shannara)
Susanna Clark - Jonathan Strange & Mr Norrell
Scott Lynch - The Lies of Locke Lamora
George R.R. Martin - A Game of Thrones (Song of Ice & Fire)
China Mieville - Perdido Street Station
K.J. Parker - Colours in the Steel (Fencer Trilogy)
Tim Powers - Last Call
Andrezj Sapkowski - The Last Wish
Jonathon Stroud - The Amulet of Samarkand (Bartimeaus Chronicles)
UNCLASSIFIABLE
Douglas Adams - The Long, Dark Tea-Time of the Soul
Robert Asprin - Another Fine Myth (Myth Adventures)
Gary Gygax - Player's Handbook & Dungeon Master's Guide (1st Edition)
Ian Livingstone - The Warlock of Firetop Mountain
Terry Pratchett - The Colour of Magic (Discworld)
*31 books, 2 series, a pair of rulebooks and 1 short story.

I think you're missing a huge Military classification with Jordan, Drake, Cook and Gemmell
Posted by: Warlock | October 29, 2009 at 04:32 PM
The Mists of Avalon...sigh...brilliant work.
I have to say that I'd add The Mistress of the Empire series by Janny Wurts and Raymond E. Feist - absolute genius!
Great list.
Posted by: Samantha | October 29, 2009 at 07:33 PM
Very nice list.
Posted by: The Mad Hatter | October 29, 2009 at 07:50 PM
I'm not nearly so broadly read as you are, although I am clearly in the 'Modern Fantasy' camp.
I tried to read Susanna Clark, but it just failed to hook me.
Lies of Locke Lamora is a fine, fine book.
Posted by: Den | October 30, 2009 at 09:41 AM
Jonathan Strange is a weird one. For THE shit-hot book of 2004, it has dropped off the radar entirely (movie in 2010 may bring it back).
I think it exemplifies a type of intellectual fantasy - detailed world-building that focuses on social detail & the process of magic (like Lev Grossman's The Magicians). For some reason, grounding magic by making it seem like a system or science makes for great fantasy - probably because it makes magic seem *almost possible*. Wish fulfillment!
Anyway, that's what I think about that :)
Posted by: Jared | October 30, 2009 at 09:51 AM
For classics:
Hope Mirlees: Lud-in-the-Mist
Burroughs: lots should fit in here.
HPL (fill in your fave) - unless you are keeping him for your essential horror?
Personally, I don't like your "Modern" category, since I'm not sure what, other than publication date, qualifies a book in this category.
That said, I'd vote to add some Lisa Goldstein (Dark Cities Underground to be specific, or Walking the Labyrinth, although DCU is probably a better book.)
IMHO, I think Moorock would scream at being added into a high fantasy category. Elric was done to spoof/mock the category :-)
Plus, before you add Lynch, I'd add Cook or Brust, as both of them did it more originally and better than did Lynch (not that I'm opinionated or anything.)
Posted by: arin | November 03, 2009 at 02:12 PM
Lud-in-the-Mist was a big oversight. I had a hard time with Burroughs, but stuck with Tarzan as his one.
HPL is definitely be reserved for horror... you know me too well.
I'm not sure what "Modern" means either. But it felt kind of natural - and slightly more broad-ranging than "Low Fantasy" (as that would've excluded a few).
I stuck Moorcock on High Fantasy because I think it is essential reading for that sub-genre, for all the reasons you mentioned (actually, I had the D&D books in High fantasy for similar reasons - another way to picture the same core elements, I guess?).
Who is Brust?! I'm well up to read anyone that can out-Lynch Lynch!
Unrelatedly, tried to re-read Wishsong of Shannara the other night, and crashed out of it pretty quickly. That series has not aged well for me.
Posted by: Jared | November 03, 2009 at 03:04 PM
shannara is still horrible. I'm surprised that you managed to rec any of them :-)
Brust = Steve Brust. Read either his Musketeer pastiches (aka the Khaavren romances) or my faves...the Taltos series (taltos and jhereg being the first two.)
I haven't recced those to you yet? Shame on me!
Posted by: arin | November 04, 2009 at 06:45 PM
I reeeeeally liked Elfstones as a kid, mostly because the demons were so cool. The series I HATED as a kid was 'Heritage' - but now, looking back at it, I think it was oddly progressive. Heritage is post-apocalyptic Shannara. Brooks wrote the original trilogy, then, sometime between Wishsong (urgh) and Scions, the bad guys won. Brilliant concept, and occasionally even 'ok' execution. Not sure it needed 4 books though. (and the ending to the Heritage series was pretty awful)
I'll check out Steve Brust. PERHAPS ON MY KINDLE.
Posted by: Jared | November 04, 2009 at 06:52 PM
I'm pretty sure I never made it to Heritage. (Being too old when they finally made it out.)
So let me know what you think of the Kindle. Still too big and too expensive for what I'm looking for, I think. I keep to my phone for now.
contact me if you want to borrow my ebooks of the taltos stuff....
Posted by: arin | November 06, 2009 at 01:31 PM