Tolkien's Middle-Earth material. Makes me sad how badly the movies killed the spirit of the books.
Michael Moorcock's Eternal Champion stuff, especially the Elric and Von Bek material. (the recent stuff is not as good, but still cool)
RE Howard's Conan, Solomon Kane, and Cormac Mac Art (can't speak for his other work)...
Fritz Leiber's Fafhrd and Grey Mouser material is worth several look-sees. I wish I had books where the stories were presented in the order they were written instead of the chronological order for the characters (actually, I wish I had it both ways.
).
Dave Sim's Cerebus is absolutely insane. Seriously, Sim is a lunatic. But the books are emotionally crushing stuff.
WaRP's original Elfquest run was fan-fucking-tastic.
Lovecraft has to be included here. "Fantasy"? "Horror"? A definite blending of the two. Maybe horror is just fantasy where the heroes can't kill the monster in the cave.
Some of Poe's stuff should fit right in here.
HG Wells has a good body of fantasy fiction. I haven't read so much of Jules Verne but the stuff I have read is pretty cool. 19th Century fantasy is the r0xx0rz.
I am interested in, but have never ready anything by, work from Lord Dunsany, Clark Ashton Smith, Robert W. Chambers, and Jack Vance. I think my delay is that I like "the full works of..." series where I'm not hunting down books of random stories where I'll end up with some stories multiple times and cra.
... and I avoid Goodkind, Jordan, Lackey like the plague.