PC Hodgell's Kencrath Chronicles is one of the best fantasy series I have ever read. It isn't well known because she is a slow writer and she keeps losing her publishers to bankruptcy. They are: God Stalk, Dark of the Moon, Seeker's Mask, To Ride a Rathorn, and Blood and Ivory (short stories). They are currently available as eBook from Baen (I believe). I keep extra copes because I wear them out.

Mark Simmons' Dreamland Chronicles and Half-Life: First series is finished (so he says) and is set in a series of virtual worlds. The second series is best described as Dracula meets the Godfather by way of Monty Python.

Glen Cook's Garrett PI: A human investigator working in a fantasy worlld of elves, vampires, unicorns, etc.

Susan Cooper's The Dark is Rising: The second book has been made into a movie, please don't judge the books by that movie. The books are tons better. The biggest insult is a critic refering to this as a Harry Potter rip-off ... this series was written a good three decades before HP was even thought of. It timeless, a wonderful blend of Arthurian legend with the fight between good and evil.

Robert Adams' Horseclans: Very rough and tumble, doesn't cut corners. Set 800 years on the future after a war has reduced civilation to medivel cities and wandering nomads. The real sad thing is that the author died before finishing the series (18 books of a planned 30 book series).