No, that wasn't the right one, try this link. It is on LJ somewhere, but my bookmarks go to fan sites instead.
Oh I remember it now. Yes. That's Angel.

Yes, and I love the triangle. Buffy sees all these "new" sides to Angel, and Spike is there to say 'No he was like this all along.' I think it says a lot about all three characters.
That is... pretty succinct. Although there's less of the Buffy-finding-things-out-about-Angel, and more Spike-and-Angel find out who each other are.