My personal favorites have been:
Sword of Truth - Terry Goodkind
The Coldfire Trilogy - C.S. Friedman
Otherland - Tad Williams (have been hearing good things about Shadowmarch but still undecided)
The Lies of Locke Lamora & Red Seas Under Red Skies - Scott Lynch
Inheritance Cycle - Christopher Paolini (Still waiting on the final book)
Wheel of Time - Robert Jordan (Still waiting on the final books)
There are many more that I really enjoyed reading...But those above tend to stick out the most for me.
Sword of Truth - Terry Goodkind
The Coldfire Trilogy - C.S. Friedman
Otherland - Tad Williams (have been hearing good things about Shadowmarch but still undecided)
The Lies of Locke Lamora & Red Seas Under Red Skies - Scott Lynch
Inheritance Cycle - Christopher Paolini (Still waiting on the final book)
Wheel of Time - Robert Jordan (Still waiting on the final books)
There are many more that I really enjoyed reading...But those above tend to stick out the most for me.