He and Martin (Maybe I'll throw in Rothfuss after I read Day 2) are almost all you need as a fantasy fan. Everything else is just filler.
Yeah...I think you over did it there by a bit. Even if you say you only meant "in progress" series, you are short-changing a ton of authors. There have just been too many great authors in fantasy for your statement to be considered valid. I mean, it's great that you love those three authors--most of us agree that those three are fantastic. Just don't get carried away by fandomonium.
As a fantasy fan, I need far more than those three authors--and I don't mean that as a slight. Abercrombie, Lynch, Erikson, Bakker, Lloyd, Barclay, Gaiman, Pratchett, Tchaikovsky, Jones, Esslemont, Enge, Scholes, Wooding, Cook, Simmons, Mieville, etc, etc, etc. You see what I mean? And these are just the people with current series. And just SOME of the authors who make up a portion of the backbone of fantasy (Martin and Sanderson obviously fit the bill as well as Rothfuss). It's all a giant puzzle, and I feel that the continued monetary and critical success that all these authors enjoy is all interlinked.