Snarky fics! Spike must be a jerk, Buffy can be... whatever, but sassy enough to snark back. Preferably not a oneshot. (And indicate if it's a WIP.)

The Kiss by ssddgr on Elysian Fields..

Pam S

Tons of excellent snark and banter in:

Closer and Closer
by Dampersandspoons

Summary: Spike Pratt is eighteen, pissed off, fresh out of jail and thrust into the arms of his stuffy uncle, Rupert Giles. Their history is unclear to Rupert's co-worker Joyce and her daughter Buffy, but what is abundantly clear is everyone's inability to communicate. The game of push me pull you can only last so long before someone finally gets close enough to make contact. And when they do... what secrets will they find?

Available on the Elysian Fields archive.
(not finished, but very long -- and very good)

When the Price is Right by Goldilocks.