I'm another 'not really a fan' fan of Donaldson. The Thomas Convenant books are certainly original in the protagonist slot, but i get rather depressed reading those books. I read the first trilogy, and the first (or two) book of the second one, but I just couldn't go on. Still have the books on my shelf somewhere, but unless I really don't have anything else to read or reread, I won't go back to them. The other serie I read from Donaldson, Mordant's Need, I found much more enjoyable... It also has a rather unlikely hero, and has also some really depressing parts, but it isn't as bad as the Thomas Covenant books. Also, Mordant's Need has a really original magic system...
The Robin Hobb trilogy of trilogies was something I also enjoyed reading.
On the SF side of things, I really like the books by Peter F. Hamilton... If you enjoy books thick enough to build a house with, be sure to check him out...
Also, Lois McMaster Bujold (Miles Vorkosigan serie), Elizabeth Moon (The Seranno Legacy and Vatta's War) and Anne McAffrey (The Chronicles of Pern if you consider these SF, and Tower and the Hive serie) are some really enjoyable writers.
Back to fantasy, if you like some horror with your fantasy, you might like Laurell K. Hamilton (Anita Blake and Meredith Gentry series) and Kelley Armstrong (Women of the Otherworld). These three series take place in a recognizable modern world but with the twist that vampires, werewolves and other magical / demonic creatures do exist which make for some original stories. Although I do have to warn you that the later books by Laurell K. Hamilton contain a rather large portion of sex... If this is bad or good, I leave to the reader...
but I certainly wouldn't mind if it wasa bit less...