Best FF Containing Both a Threesome and a Triangle, Thus Winning the Author an "Overachiever Times Three" Award:The Sword Series, by guede_mazaka. Pirates of the Caribbean, Jack/James/Will. (Story link will take you to a page with links for all six segments.) This series is not for fans of Elizabeth, since she dies in the prologue. But if there are Elizabeth fans out there, I can't think why they're reading this blog. In any case, Guede removes the pivot of the One True Foursome and takes the remaining three on a hell of a ride.
Best FF That Demonstrates Certain Entirely Off-Label Functions of Wolverine's Claws: All of the Animals, by Jane St. Clair. X-Men movies, Jean/Scott/Logan. I believe I may have already mentioned my sincere love for Jane St. Clair. This is the story that cemented that; she actually found a solution for the damned Jean/Scott/Logan triangle that works. Until I read this, I thought the only reasonable way out would involve four bullets: one for each of the characters and one for whoever thought of the triangle in the first place. And this story does something else amazing, too - it makes Scott, the world's most anal-retentive superhero, into a sympathetic character. The canon writers never managed to do that.
Best X-Men FF Containing a Harry Potter Reference: Sweep the Ashes, by penknife. X-Men movies, Magneto/Mystique/Pyro. I'm not sure what it is about the X movieverse that leads to so many multiple pairings, but I'm not complaining. Just the Magneto/Mystique/Whoever Mystique Wants to Be Today FFs could fill a book, and it'd be a good book, too. This one stands out not just because it's a real threesome - Pyro's there in person, as opposed to in Mystique - but also because Erik is so classically Erik; who else would say the last line of this story in just that way?
Best FF That Teaches an Important Life Lesson Via Sex: What Is Me and What Is Mine, by weirdnessmagnet. Teen Titans (don't worry if you haven't read or seen or whatever it is you do to this canon, because I read the story without having heard of the fandom before), Kon/Tim/Dick. If you ever meet an adult who doesn't understand the importance of sharing, direct him or her to this FF. It's smut with a moral! (My god, if this keeps up we're going to have educational slash pretty soon. Hmmm. Anyone feels like writing one, I wouldn't at all mind learning about, say, automobile repair via fan fiction.)
Best Undershirtkink FF (and I'm Sorry to Report That I Actually Can Think of Other Undershirtkink Stories): Restitution, by helenish. The Sentinel, Jim/Blair/OFC. One of the more involved true triangles out there. This one also gets extra points for having Blair do exactly what every man does when he finds out a girlfriend has slept with a friend of his: ask for a point-by-point comparison. And it wins extra extra points for the whole "Blair is vanilla" line. Didn't you always know Jim would be the kinky one?