The best currently-working fantasists:
1)
George R. R. Martin - gets the nod for #1 because of the scope of his work. An epic fantasist always nudges ahead of a novel-by-novel fantasist of the same skill. His realistic characterizations, his humanization of both pro- and an-tagonistic forces, is a breath of fresh air in a mostly stale genre. Plus, he's not shy about wielding the headsman's axe.
2)
Guy Gavriel Kay - a better writer than Martin, but works on a smaller scale. The
Fionavar Tapestry was well-written, but was fantasy fluff, and not worth reading.
Tigana, on the other hand, is the single best single-volume fantasy work ever penned. That alone would be saying something for Kay as an author, but doesn't say nearly enough once one realizes that
Lions of Al-Rassan is the 2nd best single-volume fantasy novel ever penned. Toss in the two-volume
Sarantine Mosaic, and his body of work is easily the equal of any writer in the genre. Like Martin, he's not nearly so simplistic as to stuff novels through the good-vs-evil cookie cutter. His characters are all generally their own protagonists, but with competing agendas. His works are largely based on fantasized versions of medieval-and-older Eurasia. And avoid at all costs looking too closely at the paperbacks if you're making the choice about whether to read them. The pictures on the front are always kind of girly and romance-novel looking. The descriptions on the back talk about subjects that'll make you put the books down in a hurry. But all of that belies the fact that the books are all taught fantasy-political thrillers, crammed full of murder, mayhem, rapes and assassinations galore, and some of the most memorable characters I've ever read in ANY genre.
3)
Tim Powers - It is an out and out tragedy that this guy isn't getting more play here. This guy is a flat-out master of the weird plot, and writes at what amounts to a grad-school level if taken relative to the 2nd grade offerings of the Eddings, Brooks, Weis & Hickmans, Jordans, and Goodkinds of the genre. His fantasy is...well...tilted sort of toward the arcane? I guess that would be the best way to describe it. THE place to start is with
Last Call, and the fact that this isn't one of the most talked-about books in the FFA can only mean it has zero exposure here. A combination of the Fisher King legend with Vegas and a super-high-stakes poker game played with a magically imbued tarot deck. Yes, it's pretty much a fantasy novel about
poker. It's also brilliantly written, positively thrilling, and Weird as hell. (Note the capital "W.") Powers's books are all fascinating.
Anubis Gates is the most famous (time travel done in a completely non-standard way),
Drawing of the Dark is a cross of beer and mythology, and how can you beat THAT combo?, and
Declare crosses up those arcane forces with WW2. The man is a monster. Read him.
4)
China Mieville -
Perdido Street Station and
The Scar are both set in his same, completely made up, COMPLETELY original world. Nice to see somebody writing in a fantasy setting that he's actually put some original thought into, rather than re-hashing the same old medieval Europe/Wizards and Warriors stuff. And he's got serious writing chops, to boot.
5)
Gene Wolfe - Wolfe actually straddles the line between SF and F, which is the only reason he rates so low on a fantasy list. HEAVY reading. I mean heavy like Tolstoy. Not for the casual reader at all. But very rewarding, and well worth the effort, if you've a mind to savor one of the legitimately finest
writers the genre has to offer rather than simply sucking down another whiz-bang story. The man is deeply, densely literary. He's genuinely one of the few writers out there putting SF/F back on the map at universities across the world. Somebody should send him a nice fruit basket. Read anything, just make sure you don't jump in in the middle of a series. (Most of his stuff is short story collections or multi-book series.)
On an aside, if you've read and loved Tolkien, but haven't read
Mervyn Peake's Gormenghast books, shame on you. Same era, same caliber, BETTER prose writing (by far), smaller scale (by far -- what Tolkien did to a world, Peake did to a castle), and oh yeah, he went mad from syphillis and died about the time he was finishing.
Guily pleasure:
Terry Pratchett. He's not going to win any meaty awards, but he's pretty much the Simpsons of the genre. Always good for a chuckle, always quick and easy, and you can pick up pretty much any book he's ever written and jump right in without missing anything. Also, his books are only chapterized by using a little bit of white space between scene shifts. This happens every couple pages at most, so there are TONS of good stopping spots.

Taken all in all, the finest light travel reading you can stuff in your briefcase/computer bag.