Any long tedious series worth reading?

I've stayed away from most series that go on indefinitely, but are there any worth trudging through?  This includes licensed drivel such as D&D, Battletech, Shadowrun, MTG, Battlemage, Warhammer, Dr Who, Xena, Buffy, Marvel or DC based novels, Star Trek, Star Wars, and any series which exists to promote future sequels (including Harry Potter, Wheel of Time, etc).

Glen Cook's Black Company is worth following. Sane with the Amber books.

>>20

The Sword of Truth was ok in junior high, then when I grew older I realized how awful it was - creepy randian propaganda at its worse. AVOID.