oh, i also recommend all of stephen r donaldson's stuff, but for straight up fantasy, the mordant's need pair of books are the best: the mirror of her dreams, and a man rides through
i'd totally let thomas covenant do my dumper
I love the Covenant stuff* and would recommend it above almost anything else in the genre but can barely remember the Mordant's Need stuff. I thought it was generic tosh at 14 or whatever age I was when I read it. Then again, maybe the intervening years of cubicle dotage has dulled my brain to the point where I can enjoy it.
* I even bought a hardback edition of some guy's Master's Thesis on the series, which was a trip
Jack Vance's Lyonesse stuff is a hoot, though very whimsical. Which is not to say gay. But it's getting there.
I'll second the Fritz Leiber recommendation.

Fafhrd & Grey Mouser

. He's an excellent prose stylist as well as great storyteller.
Recently, Jonathan Strange & Mr. Norrell is great. China Mieville's stuff is wonderfully dark and strange and absolutely 'fantasy' in the dictionary definition sense but I'm not sure it'd be to your taste. There are occasionally swords, and definitely sorcery, but it's very much it's own thing.
And jesus christ PD, if you haven't read LOTR, do not go anywhere near extruded pseudo-Tolkien dreck like Robert Jordan, Terry Brooks or David Eddings. I've read enough of all of those guys (thanks to my shoplifting friends in high school) to know that they do not belong in the same conversation as real writers.
If you like George R.R. Martin stuff, check out 'Tigana' by Guy Gavriel Kay. (not a series but very substantial)
A lot of Neil Gaiman's output qualifies as fantasy - American Gods is my favorite but YMMV.
Will no doubt add more once as they come to me.