The Barbverse is brilliant, isn't it? I followed it since the start, and I'm still waiting for her to update POM.

Couldn't agree more. Barb manages do do all the characters justice and write a plot that actually makes sense - something the show could only dream of at that point. She manages to realise all that potential the show let fall by the wayside.

Hmmm... off the top of my head... You've probably read Dancing Lessons, but how about Miss Murchison's Chiaroscuro? That's another good one. And all of Nan Dibble's. Also Caro's stuff. I'll dig up links for you tomorrow, okay?

Okay, here's what I've got:

Dancing Lessons, a trilogy by various authors. The project collapsed before the last part of the third novel was published, but you can skip the third book if you like - the others stand on their own.)
The website died when the project collapsed, but the story is now archived here (go back to the earliest entry for the beginning).

Chiaroscuro by missmurchison, a novel-length story that does justice to all the characters, and has a great plot too. (Her other stories are worth checking out too, especially Secret as the Grave.)

The Old Blood Series by nandibble:
Old Blood
Blood Kin (aka The Enemy of my Enemy)
Blood Is the Life
Blood Rites
Blood Price (on her LJ, nandibble)
This one goes in a different direction with the vampires, so I'm not sure if it's going to be exactly to your taste, but it's fabulous writing and very true to the characters if not the metaphysics of the show. The last story wasn't finished when she died, but there's no cliffhanger or anything on the story before.

Life in Sunnydale by spikewriter, here - another WIP that is substantial enough to have good stopping points in between if you don't want to deal with the open-endedness. Also of her other (finished) writings, I'd definitely recommend Secrets and Lies.

Let me know how you liked those! I can probably dig up a few more, but those should keep you busy for a while if you haven't read them yet. :-)