I agree, the Pern books are wonderful. And the Harper Hall trilogy is my fave within that series, with Dragonsdawn a close second.
I lean more towards fantasy than scifi (although Elizabeth Moon has done some good military scifi that I've liked), so...
Ellen Kushner- she's known for mostly short stories and as an editor, but she's written a couple of novels, Thomas the Rhymer and Swordspoint. Both are wonderful. (I've also seen mentions of a book titled Basilisk, but I haven't read it and I can't get details. Sorry)
Sharon Shinn- wonderful stuff, especially Archangel. It has two sequels, both good as well.
Robin McKinley- I love this postAuthorID. You might not, but hey. My favorite books of hers, The Blue Sword (one of my faves of any kind) and The Hero and the Crown, are technically for teenagers, not because they're shallow but because they're short. The Blue Sword, especially, reads like some weird child of Tolkien, The Sheik, and Lives of a Bengal Lancer, with a girl hero.
Connie Willis- pretty much all good. I favor Doomsday Book since it involves the plague. To Say Nothing of the Dog is just as good, though, and she's written lots more.
James Morrow- but not if you're easily offended, religiously speaking. Towing Jehovah- God dies and falls into the ocean, so he (He, I guess) has to be moved. and its sequel, Blameless in Abaddon- God's body is now the main attraction in a theme park. Only Begotten Daughter- Julie Katz, half-sister of Jesus, grows up in Atlantic City. This is the Way the World Ends- nuclear holocaust, naturally (a bit dated since the end of the Cold War, but good). plus several others. Funny, bitter, very sharp satire from a scarily smart man.