How long are you talking about? For a short series, it would be Chess Game
by urbanslut. But that one is only four very short chapters.
If you are referring to a longer epic piece, I would go with Etaski's Sisterhood
series. This is actually a series of series, starting with the four part Sisterhood and then continuing through Subterrane, Sufferance, and Surfacing. It's all one continuous story.