WoT
I am currently GMing a WoT campaign and it is a lot of fun. Playing in the Westlands can be a lot of fun, if you do it right, and aggravating, if you do it wrong.
The easiest way to do the campaign is to start it after the last of the (published) books. This way you don't worry about messing with RJ's story. But my players think its fun to play between the lines in the actual story line. If you read the books carefully you notice a lot of down time. They are traveling from place to place, or, as in the Hunt for the Horn, they simply loose a few months. My PC's enjoy operating in these down times- doing there adventures, etc- and then at the end of longish sub-campaign they find themselves in the middle of one of the book grand endings.
Another fun thing to do is play before the dragon is reborn or in one of the lands beyond the westlands: Seanchan, Tremalking, Shara, or the Isle of Madmen. That way you still get the great atmosphere of WoT but little of the plot...