I've read a lot of fantasy novels over the years, starting in grade 6 with pulp Forgotten Realms novels and Choose-Your-Own-Adventure books (I remember having like 80 bookmarks in those types) and subsequently moving to Dragonlance and Dark Sun, etc. Then I started with Terry Brooks, Dennis L. McKiernan, J. R. R. Tolkien and multiple others.
Let's be very clear: fantasy novels definitely follow Sturgeon's Law, which is "90% of everything is crap".
(You can find this in the forward in Callahan's Cross-Time Saloon, as an anecdote by author Spyder Robinson. Basically, at a convention someone said "90% of sci-fi books are crap", to which Sturgeon replied "Actually, 90% of everything is crap".)
There are a few rare gems: Dragondoom, the Silmarillion and... the Song of Ice and Fire series by George R. R. Martin.
I've just started to re-read his first three (Game of Thrones, A Clash of Kings, Storm of Swords) because his fourth is due out in the near future, and they're amazing novels for many reasons, but outstanding fantasy novels for one reason alone: there is no nemesis or poetic justice. I.e., good guys get hurt in nasty ways, bad guys win as often as not, "good guys" aren't straight out good, no one is what they seem. The entire series is driven by politics and intrigue, and the desires of the narrative's central figures (of which there are many, both crooked and mostly-good).
The big selling point for me was a well-developed political world and a gamut of pivotal characters. He also dives into central characters' PoVs in true third-person narrative style: every chapter is told from a different character's perspective. Also, and this seems like a no-brainer but most fantasy novelists are unable to convey this... the characters grow and change over the course of the writing. Often, a perceived 'good guy' will show himself/herself to be rotten, 'bad guys' will emerge as simply pragmatic or misunderstood and misrepresented, etc.
Brilliant books all 'round, but a warning: don't read them if you can't stomach some harsh writing. The guy doesn't pull any punches, and characters you love and have followed for a book or more will suddenly find themselves perished in not-so-nice ways via treachery, sickness, character foibles, or simply through common mishap. (Don't you ever wonder why people don't break legs from a simply fall or why they only take wounds in the shoulder or thigh in most fantasy novels? Pretty stupid if you ask me.)
Anyway, enough praise for Mr. Martin. Also, I encourage anyone and everyone to read "The Virtues of War" and "Gates of Fire" by Steven Pressfield. Phenomenal historical fiction set in the Classical period (Alexander the Great and Battle of Thermopylae, respectively).
Guess I should work.