(You can name the actual story whatever you want.)

The Setup:  Somehow, during S4 or S5, Buffy meets William.  It can be because she's thrown into the past, or he's thrown into the future, or Spike is put under a spell that makes him act all William-y.

And...somehow, it actually makes her miss the vampire.

It's not that he's a nerd; the poetry's bad, sure, but sweet.  The problem is that he's Victorian.  Big with the gender roles and manners, not big with the being useful.  The more time Buffy spends with him, the more she misses her former mortal enemy.  Whenever she gets back to Spike/William returns to where he came from, Buffy understands him better--but she also appreciates a lot of his more demonic aspects.

If Briley is canon at this point, then you can have Riley getting insecure over the way Buffy treats William because he's a normal human.

I feel like this would work best as a short, comedic fic, but YMMV.  Spuffy doesn't necessarily have to be in a relationship by the end, but they would be the focus, of course.

Can Have:

• Buffy bringing out a more Spike-y side of William--in an unguarded moment he says something about wanting to get revenge on his own bullies, is fascinated by some kind of counterculture, etc.
• Going along with the above: Buffy initially assumes that this confirms her theory that vampires are nothing like the humans they were when they were turned, but comes to realize that the two Spike sides are very similar
• Rather than William falling in love with Buffy, he comes to consider her as sort of a role model in badassery.  It's kind of adorable.

Must Not Have:

• Claim/marriage/pregnancy
• Character bashing
• Major timeline changes--William's memory is tampered with when it's all over, or something.  The focus is on how this changes Buffy's perception of Spike after this point, not how their relationship would change before.