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).

Sword of Truth series has about 10 or 11 books out, last and final installment comes out this fall.  It's a very good series, worth checking out.