(a little nod to Rezol87 as this idea grew out of her EC chapter, however, this story isn't mine either ;-)
Author choice of title.
Post Chosen (and ignoring AtS S5 and the comics) Buffy and the crew are facing a new evil, the nature of what it is, is entirely up to the author. The kicker is, they need Spike in order to beat it. Do whatever handwaving you need to for the reason behind that and for the method by which Buffy steps across dimensions to pluck a Spike who is about to die away from his dusting with milliseconds to spare. The Spike she grabs is from S2 and he'd just had the tables turned on him by Angelus and was about to be ended in the Crawford Street Mansion.
Now the Scoobies have their Spike, but he's soulless, chipless, and still devoted to Drusilla. None of which a heart-eye'd Buffy really had time for. She's so overjoyed to see him that she keeps sort of throwing herself at him, much to Spike's embarrassment. I'm hoping for a few chapters here of sexual frustration on both their parts (bonus if they both are getting themselves off, angrily of course).
Mostly what I want to see is a Spike that's attracted to, but not in love with, Buffy, being snowed under by the full force of her love. Eventually, he's of course going to fall head over heels for her sooner or later (smut is good!).
Drusilla can show up at some point, but I really don't want Spike running off or boinking her in order to figure out he doesn't want to be with her. Buffy being jealous would be a bonus, though.
I'd also like angel to show up and for Spike to be floored when Buffy won't have much to do with Angel and his soulful act.
In the end, the defeat the newest evil monster and live happily ever after.
I'd like to see Dawn forge a relationship with this Spike during the course of the story, who despite himself can't help but care for her. Maybe Dawn can get herself kidnapped at one point and Spike is the one to save her.
The "nos"" are: 1) no evil scoobies, no scoobie bashing, no reading Xander, Willow or Giles a long list of everything they did wrong and Buffy yelling at them that they should pay for it. 2) no torture of anyone at any point 3) Spike can't murder and eat anyone. He can get close, but just no. At first Buffy is watching him like a hawk, and later he realizes that he really doesn't want to risk the new life he's found.
Pretty much anything else is fair game! I'm hoping for lots of snarky banter, sexual tension, eventual smut, and a HEA.