C.S. Lewis, (Chronicles of Narnia) and Andrew Peterson (Wingfeather Saga).
Quite a few: Michael Moorcock; Fritz Leiber; Ursula K. Le Guin; Roger Zelazny; Robert E. Howard; David & Leigh Eddings; Harlan Ellison; Jim Butcher; H.P. Lovecraft; Lloyd Alexander; Neil Gaiman; Jeff Smith; Edgar Rice Burroughs; Wendy & Richard Pini; Terry Pratchett; Robert Asprin; etc.
Keep in mind that I can like a writer's body of work without approving of all of their personal views.
I will echo andrewlaubacher's post, plus RA Salvatore (Icewind Dale trilogy), Margaret Weiss and Tracy Hickman (Dragonlance Trilogy) and Terry Brooks (Sword of Shannara). I prefer the early works of these authors. I'm okay with trilogies, but I find multi-book series too tedious to keep up with.
I'm not quite as enamoured of the Dragonlance books, and I lost much of my taste for Salvatore's Drizzt Do'Urden novels after the first few books. I was excited to learn that he was to be the story editor for SciFi's Forgotten Realms series before that project fell through. Other D&D authors I really like include Troy Denning, Elaine Cunningham, James Lowder, David Cook, and (of course) Ed Greenwood who originated the Forgotten Realms campaign.
I just read Dune and Dune Messiah. They were well-written and all that, but there was just too much politics for me to really enjoy them. I read scifi for fun stuff, not dynastic bickering. Other than that, C.S. Lewis is always excellent, especially since you can read it in 3rd grade, grow up and go to college, then read it again and still learn something. Christopher Paolini isn't a master writer, but darn is Eragon fun to read. Saphira is the most adorable character I've ever seen and I like how Paolini magic obeys the laws of energy conservation. I'd like to get into Lovecraft, but probably not until next summer when I don't have a mountain of textbooks to read.
A lot of Clark Ashton Smith's work can be found in this website:
Clark Ashton Smith is another favorite.
I've read Clark Ashton Smith as well as a poetry collection by another member of Lovecraft's circle, Frank Belknap Long.
Nowadays I'm more into nonfiction, but I still enjoy a short story as well.
Brent Weeks The Night Angel Trilogy, Lightbringer
John Flanagan The Ranger's Apprentice
David Stewart Needle Ash
Terry Brooks The Shannara Chronicles
Dungeon and Dragons short story novels
Markus Heitz The Dwarves book 1, The War Of The Dwarves book 2
Rick Riordan Percy Jackson novels
Anne Rice The Vampire Chronicles.